[424B7] GRAIL, Inc. Prospectus Filed Pursuant to Rule 424(b)(7)

Rhea-AI Filing Summary

GRAIL, Inc. filed a prospectus supplement for the resale of up to 3,925,767 shares of common stock by selling stockholders. The registration covers 1,927,194 outstanding common shares and 1,998,573 shares issuable upon exercise of pre-funded warrants.

The company is not selling shares and will not receive proceeds from holder sales; it would receive the nominal $0.001 per-share exercise price if pre-funded warrants are exercised for cash. Selling holders may use various methods of sale, including brokerage transactions, block trades, privately negotiated deals and short sales after the registration statement is declared effective.

Examples include Deep Track Biotechnology Master Fund, Ltd. 927,909 and Farallon affiliates 571,021. Shares outstanding were 38,981,593 as of October 31, 2025. GRAL trades on Nasdaq Global Select Market; the last reported sale price was $84.77 on November 12, 2025.

Filed Pursuant to Rule 424(b)(7)

Registration No. 333-291503

PROSPECTUS SUPPLEMENT

(To Prospectus dated November 13, 2025)

GRAIL, Inc.

3,925,767 Shares

Common Stock

Offered by the Selling Stockholders

This prospectus supplement relates to the proposed resale or other disposition from time to time of up to an aggregate of 3,925,767 shares of common stock, par value $0.001 per share, of GRAIL, Inc. (the “common stock”) by the selling stockholders named in this prospectus supplement (the “selling stockholders”), which consists of: (i) 1,927,194 shares of our common stock and (ii) 1,998,573 shares of our common stock issuable upon the exercise of pre-funded warrants to purchase shares of our common stock. We are registering the offer and sale of the shares covered by this prospectus supplement to satisfy registration rights we granted to the selling stockholders pursuant to that certain registration rights agreement, dated October 18, 2025, by and among us and the selling stockholders in connection with the selling stockholders’ purchase of shares of common stock or, in lieu thereof, pre-funded warrants to purchase shares of common stock in a private placement (the “2025 Registration Rights Agreement”).

The selling stockholders may, from time to time, sell, transfer, or otherwise dispose of any or all of their shares of common stock covered by this prospectus supplement on any stock exchange, market, or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices. See “Plan of Distribution” beginning on page S-17 for more information about how the selling stockholders may sell or dispose of their shares of common stock hereunder.

We are not selling any shares of our common stock under this prospectus supplement and will not receive any proceeds from the sale or other disposition of the shares of common stock covered by this prospectus supplement by the selling stockholders. Upon any exercise of the pre-funded warrants by payment of cash, however, we will receive the nominal cash exercise price paid by the holders of the pre-funded warrants. We intend to use those proceeds, if any, for general corporate purposes. The selling stockholders will bear all costs, commissions and discounts, if any, attributable to the sales of the shares of common stock covered by this prospectus supplement. We will bear the fees and expenses incurred in effecting the registration of the shares of common stock covered by this prospectus supplement, including, without limitation, all registration, filing, and printing fees and expenses, and fees and expenses of our counsel and our independent registered public accounting firm.

We may amend or supplement this prospectus supplement from time to time by filing amendments or supplements as required. You should read the entire prospectus supplement and any amendments or supplements carefully before you make your investment decision.

INVESTING IN OUR COMMON STOCK INVOLVES RISKS. SEE THE SECTION TITLED “RISK FACTORS” ON PAGE S-4 OF THIS PROSPECTUS SUPPLEMENT AND ON PAGE 6 OF THE ACCOMPANYING PROSPECTUS CONCERNING FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN OUR COMMON STOCK.

Our common stock is listed on the Nasdaq Global Select Market under the symbol “GRAL.” On November 12, 2025, the last reported sale price of our common stock on the Nasdaq Global Select Market was $84.77 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is November 13, 2025

TABLE OF CONTENTS

Prospectus Supplement

			Page
ABOUT THIS PROSPECTUS SUPPLEMENT			S-1
THE COMPANY			S-3
RISK FACTORS			S-4
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-5
USE OF PROCEEDS			S-6
DESCRIPTION OF CAPITAL STOCK			S-7
THE SELLING STOCKHOLDERS			S-14
PLAN OF DISTRIBUTION			S-17
LEGAL MATTERS			S-19
EXPERTS			S-19
WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE			S-20

Prospectus

ABOUT THIS PROSPECTUS			1
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			2
WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE			3
THE COMPANY			5
RISK FACTORS			6
USE OF PROCEEDS			7
DESCRIPTION OF CAPITAL STOCK			8
DESCRIPTION OF DEBT SECURITIES			15
DESCRIPTION OF OTHER SECURITIES			23
GLOBAL SECURITIES			24
SELLING SECURITYHOLDERS			28
PLAN OF DISTRIBUTION			29
LEGAL MATTERS			30
EXPERTS			30

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of common stock and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part is the accompanying prospectus, included in our registration statement on Form S-3 (File No. 333-291503), along with the documents incorporated by reference therein, which provides more general information, some of which may not apply to this offering. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus or in any document incorporated by reference that was filed with the Securities and Exchange Commission (the “SEC”) before the date of this prospectus supplement, on the other hand, you should rely on the information contained in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement.

This prospectus supplement and the accompanying prospectus are part of a “shelf” registration statement that we filed with the SEC. By using a shelf registration statement, the selling stockholders named in a prospectus supplement may, from time to time, offer and sell our common stock in one or more offerings or resales. The accompanying prospectus provides you with a general description of our securities, which the selling stockholders may offer and sell pursuant to this prospectus supplement. The registration statement also includes exhibits that provide more detail on the matters discussed in this prospectus supplement and the accompanying prospectus. You should read this prospectus supplement, the accompanying prospectus, including the information incorporated by reference herein and therein, and the exhibits filed with the SEC in their entirety before making an investment decision.

Neither we, nor the selling stockholders, have authorized anyone to provide you with any information or to make any representations other than those contained or incorporated by reference in this prospectus supplement and the accompanying prospectus prepared by or on behalf of us or to which we have referred you. We and the selling stockholders take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We and the selling stockholders will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement and the accompanying prospectus is accurate only as of the date on its respective cover, that the information appearing in any applicable free writing prospectus is accurate only as of the date of that free writing prospectus, and that any information incorporated by reference is accurate only as of the date of the document incorporated by reference, unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates.

When we refer to “GRAIL,” “we,” “our,” “us” and the “company” in this prospectus supplement, we mean GRAIL, Inc. and its consolidated subsidiaries, unless otherwise specified. When we refer to “you,” we mean the potential holders of the applicable series of securities.

GRAIL, Galleri and our logo are some of our trademarks and trade names used in this prospectus supplement and documents incorporated herein by reference. This prospectus supplement and the documents incorporated by reference in this prospectus supplement also contain trademarks, trade names and service marks of other companies, which are the property of their respective owners. Solely for convenience, trademarks, trade names and service marks referred to in this prospectus supplement and the documents incorporated by reference in this prospectus supplement may appear without the ®, TM or SM symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the rights of the applicable licensor to these trademarks, trade names and service marks. We do not intend our use or display of other parties’ trademarks, trade names or service marks to imply, and such use or display should not be construed to imply, a relationship with, or endorsement or sponsorship of us by, these other parties.

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This prospectus supplement and the documents incorporated by reference herein contain industry and market data obtained from periodic industry publications, third-party surveys and studies, and government and industry sources. Industry publications and surveys generally state that the information contained therein has been obtained from sources believed to be reliable. Although we believe the industry and market data to be reliable as of the date of this prospectus supplement, this information could prove to be inaccurate. Industry and market data could be wrong because of the method by which sources obtained their data and because information cannot always be verified with complete certainty due to the limits on the availability and reliability of raw data, the voluntary nature of the data gathering process and other limitations and uncertainties. Each publication, study and report speaks as of its original publication date (and not as of the date of this prospectus supplement). In addition, we do not know all of the assumptions regarding general economic conditions or growth that were used in preparing the forecasts from the sources replied upon or cited herein.

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THE COMPANY

We are an innovative commercial-stage healthcare company focused on saving lives and shifting the paradigm in early cancer detection. We believe screening individuals for many types of cancer with a single test represents a significant opportunity to reduce the global burden of cancer. Our Galleri test is a commercially available screening test for early detection of multiple types of cancer, which we termed multi-cancer early detection. We believe Galleri is clinically validated based on the results of its clinical studies completed to date, including the results of its foundational case-control Circulating Cell-free Genome Atlas study, interventional PATHFINDER study, data from the NHS-Galleri prevalent screening round and initial data from the PATHFINDER 2 study. In these studies, Galleri demonstrated an ability to detect a shared cancer signal across multiple types of cancer, accurately predict the specific organ or tissue type where the cancer signal originated, and yield high positive predictive values and low false positive rates, all from a simple blood draw.

Galleri results can help guide next steps for diagnosis of cancer by healthcare providers in required follow-up diagnostic testing. We launched Galleri in the United States in mid-2021. Galleri has detected some of the most aggressive cancers in early stages including, among others, endometrial, esophageal, gastric, head and neck, liver, pancreatic, and rectal cancers.

We were incorporated in the State of Delaware in connection with the conversion of GRAIL, LLC, a Delaware limited liability company, to GRAIL, Inc., on June 21, 2024. Our principal executive offices are located at 1525 O’Brien Drive, Menlo Park, California 94025, and our telephone number is (833) 694-2553. Our corporate website address is www.grail.com. Information contained on or accessible through our website is not a part of this prospectus supplement and the accompanying prospectus and should not be relied on in determining whether to make an investment decision. The inclusion of our website address in this prospectus supplement and the accompanying prospectus is an inactive textual reference only.

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RISK FACTORS

Investment in any common stock offered pursuant to this prospectus supplement and the accompanying prospectus involves risks. Before deciding whether to invest in our common stock, you should carefully consider the risk factors incorporated by reference to this prospectus supplement, the accompanying prospectus and the registration statement of which they form a part, including the risk factors in our most recent Annual Report on Form 10-K and any subsequent Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus supplement and the accompanying prospectus, as updated by our subsequent filings under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the risk factors and other information contained in any applicable free writing prospectus. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors or those that we currently deem immaterial that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also carefully read the section titled “Special Note Regarding Forward-Looking Statements.”

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the accompanying prospectus, including the documents that we incorporate by reference herein and therein contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Exchange Act, which statements involve substantial risks and uncertainties. All statements contained or incorporated by reference in this prospectus supplement other than statements of historical fact, including without limitation statements regarding our future financial performance, future tests or products, technology, clinical studies, regulatory landscape, compliance and strategy, potential market opportunity, anticipated growth strategies, sufficiency of cash on hand to finance our business, cost savings, budgets and strategies, restructuring and stock-based compensation costs, impact of the restructuring on our operations and anticipated trends in our business, are forward-looking statements. The words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “predict,” “project,” “potential,” “seek,” “intend,” “could,” “would,” “should,” “expect,” “plan” and similar expressions are intended to identify forward-looking statements, but the absence of these words does not mean that a statement is not forward looking.

You should not rely upon forward-looking statements as predictions of future events. We have based the forward-looking statements contained or incorporated by reference in this prospectus supplement primarily on our current expectations and projections about future events and trends that we believe may affect our business, financial condition, results of operations and prospects. The outcome of the events described in these forward-looking statements is subject to risks, uncertainties and other factors including those described in, or incorporated by reference into, the section titled “Risk Factors” and elsewhere in this prospectus supplement. Moreover, we operate in a very competitive and rapidly changing environment. New risks and uncertainties emerge from time to time and it is not possible for us to predict all risks and uncertainties or the extent to which any factor or combination of factors may cause actual results to differ materially from those contained in any forward-looking statements we may make in this prospectus supplement or the documents incorporated by reference herein. We cannot assure you that the results, events and circumstances reflected in the forward-looking statements will be achieved or occur. Actual results, events or circumstances could differ materially and adversely from those described or anticipated in the forward-looking statements.

The forward-looking statements made in, or incorporated by reference into, this prospectus supplement relate only to events as of the date on which the statements are made. We undertake no obligation to update any forward-looking statements made or incorporated by reference in this prospectus supplement to reflect events or circumstances after the date of this prospectus supplement or to reflect new information or the occurrence of unanticipated events, except as required by law. We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements.

Our actual results and timing of selected events may differ materially from those anticipated in these forward-looking statements as a result of many factors, including those described in, or incorporated by reference into, the section titled “Risk Factors” and elsewhere in this prospectus supplement.

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USE OF PROCEEDS

We will not receive any of the proceeds from the sale of shares of our common stock being offered by the selling stockholders. Upon any exercise of the pre-funded warrants by payment of cash, however, we will receive the nominal cash exercise price paid by the holders of the pre-funded warrants. We intend to use those proceeds, if any, for general corporate purposes.

The selling stockholders will bear all costs, commissions and discounts, if any, attributable to the sales of the shares of common stock covered by this prospectus supplement. We will bear the fees and expenses incurred in effecting the registration of the shares of common stock covered by this prospectus supplement, including, without limitation, all registration, filing, and printing fees and expenses, and fees and expenses of our counsel and our independent registered public accounting firm.

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DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock is not complete and may not contain all the information you should consider before investing in our capital stock. This description is summarized from, and qualified in its entirety by reference to, our certificate of incorporation (“Certificate of Incorporation”), our amended and restated bylaws (“Bylaws”) and the agreements to which we and certain of our stockholders are parties, each of which are incorporated by reference as exhibits to the registration statement of which this prospectus forms a part, and by applicable law. We encourage you to read our Certificate of Incorporation, our Bylaws, our Stockholder and Registration Rights Agreement (as defined below) and our 2025 Registration Rights Agreement (as defined below), each of which has been publicly filed with the SEC, and the applicable provisions of Delaware law, for more information. See “Where You Can Find More Information; Incorporation by Reference.”

Our authorized capital stock consists of:

•1,500,000,000 shares of common stock, par value $0.001 per share; and

•50,000,000 shares of preferred stock, par value $0.001 per share.

Common Stock

Dividend Rights. Holders of shares of our common stock are entitled to receive dividends when, as and if declared by our board of directors (the “Board”) at its discretion out of funds legally available for that purpose, subject to the preferential rights of any preferred stock that may be outstanding.

Voting Rights. Each share of common stock is entitled to one vote upon any matter submitted to a vote of our stockholders, including the election of directors. Holders of our common stock vote as a single class on all matters submitted to a stockholder vote, subject to any voting rights granted to holders of any preferred stock. Holders of the common stock are not entitled to any cumulative voting rights. Except as otherwise provided by the Certificate of Incorporation, the Bylaws, the rules or regulations of any stock exchange applicable to the Company, or applicable law or pursuant to any regulation applicable to the Company or its securities, each matter (other than the election of directors, as described below under “-Election and Removal of Directors; Vacancies”) presented to the stockholders at a duly called or convened meeting at which a quorum is present shall be decided by the affirmative vote of the holders of a majority in voting power of the votes cast (excluding abstentions and broker non-votes) on such matter.

Liquidation. In the event of our liquidation, dissolution, or winding up, the holders of common stock are entitled to share ratably in all assets remaining after payment of liabilities, subject to prior distribution rights of preferred stock, if any, then outstanding.

Other Rights. The holders of our common stock have no preemptive rights or other subscription rights.

There are no redemption or sinking fund provisions applicable to our common stock.

Preferred Stock

Our Board has the authority to issue the preferred stock in one or more series and to fix the rights, preferences, privileges, and restrictions thereof, including dividend rights, dividend rates, conversion rights, voting rights, terms of redemption, redemption prices, liquidation preferences, and the number of shares constituting any series or the designation of such series, without further vote or action by the stockholders. The issuance of preferred stock may have the effect of delaying, deterring, or preventing a change in control of our company without further action by the stockholders and may adversely affect the voting and other rights of the holders of common stock.

Pre-Funded Warrants

In October 2025, we entered into a securities purchase agreement with certain purchasers, pursuant to which we agreed to sell securities to such purchasers in a private placement. In connection with the private placement, we issued and sold, in lieu of shares of our common stock for certain purchasers, pre-funded warrants to purchase 1,998,573 shares of our common stock at a public offering price of $70.049 per underlying share of common stock,

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with an exercise price of $0.001 per underlying share of common stock. The pre-funded warrants are exercisable at any time.

The exercise price and number of shares of our common stock issuable upon exercise of the pre-funded warrants may be adjusted upon the occurrence of specific events, including stock dividends, stock splits, reclassifications and combinations of our common stock.

The holders of the pre-funded warrants must pay the exercise price upon exercise of the pre-funded warrants, unless such holders are utilizing the cashless exercise provision of the pre-funded warrants. The pre-funded warrants may be exercised at such time by means of a “cashless exercise” in which, in lieu of making the cash payment otherwise contemplated to be made to us upon such exercise in payment of the aggregate exercise price, the holder may elect instead to receive upon such exercise the net number of shares of common stock determined according to a formula set forth in the pre-funded warrants.

In the event of certain fundamental transactions (as described in the pre-funded warrants), a holder of pre-funded warrants will be entitled to receive, upon exercise of the pre-funded warrants, the kind and amount of securities, cash or other property that such holder would have received had they exercised the pre-funded warrants immediately prior to such fundamental transaction without regard to any limitations on exercise contained in the pre-funded warrants.

Except for the right to participate in certain dividends and distributions and as otherwise provided in the pre-funded warrants or by virtue of a holder’s ownership of our common stock, the holders of pre-funded warrants do not have the rights or privileges of holders of our common stock, including any voting rights, until they exercise their warrants.

 Certain Provisions of Delaware Law, Our Certificate of Incorporation and Bylaws

Election and Removal of Directors; Vacancies

Our Board consists of between five and fifteen directors. The exact number of directors is fixed from time to time by resolution of the Board. Directors are elected by a plurality of the votes of the shares of our capital stock present in person or represented by proxy at the meeting and entitled to vote on the election of directors.

No director may be removed except for cause, and directors may be removed for cause only by an affirmative vote of shares representing not less than a majority of the shares then entitled to vote at an election of directors.

Any vacancy occurring on the Board and any newly created directorship may be filled only by a majority of the remaining directors in office.

Staggered Board

Our Board is divided into three classes serving staggered three-year terms. At each annual meeting of stockholders, directors are elected to succeed the class of directors whose terms have expired. This classification of our Board could have the effect of increasing the length of time necessary to change the composition of a majority of the Board. In general, at least two annual meetings of stockholders will typically be necessary for stockholders to effect a change in a majority of the members of the Board.

Limitation on Action by Written Consent

Our Certificate of Incorporation and our Bylaws provide that holders of our common stock are not be able to act by written consent without a meeting.

Stockholder Meetings

Our Certificate of Incorporation and our Bylaws provide that special meetings of our stockholders may be called only at the direction of the Chief Executive Officer, the Board, or the Chairperson of the Board or the Lead

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Independent Director. Our Certificate of Incorporation and our Bylaws specifically deny any power of any other person to call a special meeting.

Amendment of Certificate of Incorporation

The provisions of our Certificate of Incorporation described under “-Election and Removal of Directors; Vacancies,” “-Stockholder Meetings,” “-Limitation on Action by Written Consent,” “-Limitation of Liability of Directors and Officers,” “-Common Stock-Voting Rights,” and “-Forum Selection” and provisions relating to amendments to our Certificate of Incorporation may be amended only by the affirmative vote of holders of at least 66-2/3% of the voting power of our outstanding shares of voting stock. The affirmative vote of holders of at least a majority of the voting power of our outstanding shares of stock is generally required to amend other provisions of our Certificate of Incorporation.

Amendment of Bylaws

Certain provisions of our Bylaws may generally be altered, amended, or repealed, and new bylaws may be adopted, with the affirmative vote of a majority of directors present at any regular or special meeting of the Board called for that purpose, provided that any alteration, amendment, or repeal of, or adoption of any bylaw inconsistent with specified provisions of the bylaws, including those related to special and annual meetings of stockholders, action of stockholders by written consent, nomination of directors, transfers of capital stock and dividends requires the affirmative vote of at least 66-2/3% of all directors in office at a meeting called for that purpose.

All other provisions of our Bylaws may generally be altered, amended, or repealed, and new bylaws may be adopted, with the affirmative vote of holders of 66-2/3% of the voting power of our outstanding shares of voting stock.

Other Limitations on Stockholder Actions

Our Bylaws impose some procedural requirements on stockholders who wish to:

•make nominations in the election of directors;

•propose that a director be removed;

•propose any repeal or change in our Bylaws; or

•propose any other business to be brought before an annual or special meeting of stockholders.

Under these procedural requirements, in order to bring a proposal before a meeting of stockholders, a stockholder must deliver timely notice of a proposal pertaining to a proper subject for presentation at the meeting to our corporate secretary along with the following:

•a description of the business or nomination to be brought before the meeting and the reasons for conducting such business at the meeting;

•the stockholder’s name and address;

•any material interest of the stockholder in the proposal;

•the number of shares beneficially owned by the stockholder and evidence of such ownership; and

•the names and addresses of all persons with whom the stockholder is acting in concert and a description of all arrangements and understandings with those persons, and the number of shares such persons beneficially own.

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To be timely, a stockholder must generally deliver notice:

•in connection with an annual meeting of stockholders, not less than 90 nor more than 120 days prior to the date on which the annual meeting of stockholders was held in the immediately preceding year, but in the event that the date of the annual meeting is more than 30 days before or more than 60 days after the anniversary date of the preceding annual meeting of stockholders, a stockholder notice will be timely if received by us no later than the 120 days prior to such annual meeting and not later than (i) 90 days prior to the date of the annual meeting or, if later, (2) the 10th day following the day on which we first publicly announce the date of the annual meeting; or

•in connection with the election of a director at a special meeting of stockholders, during the period not less than 90 nor more than 120 days prior to the date of the special meeting, or the 10th day following the day on which a notice of the date of the special meeting was mailed to the stockholders or the public disclosure of that date was made.

 In order to submit a nomination for our Board, a stockholder must also submit all information with respect to the nominee that would be required to be included in a proxy statement, as well as other information. If a stockholder fails to follow the required procedures, the stockholder’s proposal or nominee will be ineligible and will not be voted on by our stockholders.

Indemnification of Directors and Officers and Limitation of Liability of Directors and Officers

Section 145 of the Delaware General Corporation Law provides that a corporation may indemnify directors and officers as well as other employees and agents against expenses (including attorneys’ fees), judgments, fines, and amounts paid in settlement actually and reasonably incurred by such person in connection with any threatened, pending, or completed actions, suits, or proceedings in which such person is made a party by reason of such person being or having been a director, officer, employee, or agent to the registrant. The Delaware General Corporation Law provides that Section 145 is not exclusive of other rights to which those seeking indemnification may be entitled under any bylaw, agreement, vote of stockholders or disinterested directors or otherwise.

Our Certificate of Incorporation provides that, to the fullest extent permitted by law, we will indemnify any officer or director of our company against all damages, claims, and liabilities arising out of the fact that the person is or was our director or officer, or served any other enterprise at our request as a director or officer. Amending this provision will not reduce our indemnification obligations relating to actions taken before an amendment. GRAIL has entered into indemnification agreements with each of its current directors, executive officers, and certain other officers to provide these directors and officers additional contractual assurances regarding the scope of the indemnification set forth in our Certificate of Incorporation and our Bylaws and to provide additional procedural protections. There is no pending litigation or proceeding involving a director or executive officer of GRAIL for which indemnification has been sought.

Our Certificate of Incorporation also provides that no director or officer will be personally liable to us or our stockholders for monetary damages for breach of fiduciary duty as a director or officer, except as required by applicable law, as in effect from time to time. Section 102(b)(7) of the Delaware General Corporation Law permits a corporation to provide in its certificate of incorporation that a director or officer of the corporation shall not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director or officer, except for liability of:

•a director or officer for any breach of the director’s or officer’s duty of loyalty to our company or our stockholders;

•a director or officer for any act or omission not in good faith or which involved intentional misconduct or a knowing violation of law;

•a director for unlawful payments of dividends or unlawful stock repurchases or redemptions as provided in Section 174 of the Delaware General Corporation Law;

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•a director or officer for any transaction from which the director or officer derived an improper personal benefit; and

•an officer in any action by or in the right of our company.

As a result, neither we nor our stockholders have the right, through stockholders’ derivative suits on our behalf, to recover monetary damages against a director or officer for breach of fiduciary duty as a director or officer, including breaches resulting from grossly negligent behavior, except in the situations described above.

Forum Selection

Our Certificate of Incorporation provides that the Court of Chancery of the State of Delaware is the sole and exclusive forum for the following types of actions or proceedings under Delaware statutory or common law: (i) any derivative action or proceeding brought on behalf of us; (ii) any action asserting a claim of breach of fiduciary duty owed by any director, officer, or other employee of our company to us or our stockholders; (iii) any action asserting a claim arising pursuant to any provision of the Delaware General Corporation Law or our Certificate of Incorporation and bylaws; or (iv) any action asserting a claim governed by the internal affairs doctrine. This provision would not apply to claims brought to enforce a duty or liability created by the Exchange Act, as amended, or any other claim for which the federal courts have exclusive jurisdiction. Furthermore, our Certificate of Incorporation also provides that unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States shall be the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act. Any person or entity purchasing or otherwise acquiring any interest in our shares of capital stock shall be deemed to have notice of and have consented to the foregoing forum selection provisions.

Our exclusive forum provision does not relieve us of our duties to comply with the federal securities laws and the rules and regulations thereunder, and our stockholders will not be deemed to have waived our compliance with these laws, rules and regulations.

The enforceability of similar federal court choice of forum provisions in other companies’ certificates of incorporation has been challenged in legal proceedings, and it is possible that a court could find this type of provision to be inapplicable or unenforceable. If a court were to find either of the choice of forum provisions contained in our Certificate of Incorporation or Bylaws to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions.

The choice of forum provisions may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with the company or its directors, officers or other employees, which may discourage such lawsuits against the company and its directors, officers, and other employees and result in increased costs for investors to bring a claim.

Delaware Business Combination Statute

We have elected to be subject to Section 203 of the Delaware General Corporation Law. Section 203 prevents an “interested stockholder,” which is defined generally as a person owning 15% or more of a corporation’s voting stock, or any affiliate or associate of that person, from engaging in a broad range of “business combinations” with the corporation for three years after becoming an interested stockholder unless:

•the Board of the corporation had previously approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;

•upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, that person owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, other than statutorily excluded shares; or

•following the transaction in which that person became an interested stockholder, the business combination is approved by the Board of the corporation and holders of at least two-thirds of the outstanding voting stock not owned by the interested stockholder.

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Under Section 203, the restrictions described above also do not apply to specific business combinations proposed by an interested stockholder following the announcement or notification of designated extraordinary transactions involving the corporation and a person who had not been an interested stockholder during the previous three years or who became an interested stockholder with the approval of a majority of the corporation’s directors, if such extraordinary transaction is approved or not opposed by a majority of the directors who were directors prior to any person becoming an interested stockholder during the previous three years or were recommended for election or elected to succeed such directors by a majority of such directors.

Section 203 may make it more difficult for a person who would be an interested stockholder to effect various business combinations with a corporation for a three-year period. Section 203 also may have the effect of preventing changes in our management and could make it more difficult to accomplish transactions that our stockholders may otherwise deem to be in their best interests.

Anti-Takeover Effects of Some Provisions

Certain provisions of our Certificate of Incorporation and Bylaws could make the following more difficult:

•acquisition of control of us by means of a proxy contest, tender offer, or otherwise; or

•removal of our incumbent officers and directors.

These provisions, as well as our ability to issue preferred stock, are designed to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with our Board. We believe that the benefits of increased protection give us the potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us, and that the benefits of this increased protection outweigh the disadvantages of discouraging those proposals, because negotiation of those proposals could result in an improvement of their terms.

Stockholder and Registration Rights Agreement

We and Illumina are parties to a stockholder and registration rights agreement (the “Stockholder and Registration Rights Agreement”) pursuant to which we granted to Illumina certain registration rights with respect to the shares of our common stock owned by Illumina. Illumina may transfer these rights in certain limited circumstances, including in connection with an equity-for-debt exchange to a third-party lender (a “Permitted Transferee” and, collectively with Illumina, “Holders”), and such Holders will thereafter be bound by the terms of the Stockholder and Registration Rights Agreement.

Demand Registration

Holders are able to request registration under the Securities Act of all or any portion of their shares of our common stock covered by the Stockholder and Registration Rights Agreement, and we are obligated, subject to limitations on minimum offering size and certain other limited exceptions, to register such shares as requested by such Holders. Holders are generally able to designate the terms of each offering effected pursuant to a demand registration, which may take the form of a shelf registration, and are able to request that we complete up to three demand registrations in any 12-month period, provided that we shall not be obligated to effect more than five demand registration in the aggregate.

We are not required to honor a demand registration if we have effected a registration within the preceding 60 days. In addition, if we reasonably determine in good faith that filing a registration statement would be significantly disadvantageous to us, we may, no more than twice during any 12-month period, delay filing such registration statement until the earlier of 90 days after we make such determination or seven days after the disadvantageous condition no longer exists, provided that these postponement rights shall not be applicable to the Holders for more than a total of 120 days during any 12-month period.

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Piggy-Back Registration

If we at any time intend to file on our behalf or on behalf of any of our other security holders a registration statement in connection with a public offering of any of our securities on a form and in a manner that would permit the registration for offer and sale of shares of our common stock held by Holders, Holders have the right to include their shares of our common stock in that offering, subject to certain limitations.

Indemnification

The Stockholder and Registration Rights Agreement contains customary indemnification and contribution provisions by us for the benefit of Holders and, in limited situations, by Holders for the benefit of us with respect to the information provided by such Holders included in any registration statement, prospectus, or related document.

Voting Restrictions

Illumina agreed to vote any shares of our common stock that it retains in proportion to the votes cast by our other stockholders and granted us a proxy to vote its shares of our common stock in such proportion. Any such proxy, however, will be automatically revoked as to a particular share upon any sale or transfer of such share from Illumina to a person other than Illumina, and neither the Stockholder and Registration Rights Agreement nor proxy limits or prohibits any such sale or transfer.

2025 Registration Rights Agreement

We and certain investors are a party to a registration rights agreement (the “2025 Registration Rights Agreement”), pursuant to which we granted the purchasers of our common stock and pre-funded warrants to purchase shares of our common stock certain registration rights. We entered into the 2025 Registration Rights Agreement in connection with the issuance and sale by us of 2,640,970 shares of our common stock and pre-funded warrants to purchase 1,998,573 shares of our common stock in a private placement to certain investors, which closed on October 21, 2025 (the “Private Placement”).

Pursuant to the 2025 Registration Rights Agreement, we agreed to prepare and file a registration statement with the SEC within 30 days after the closing date of the Private Placement for purposes of registering the resale of the shares of our common stock and the shares of our common stock issuable upon exercise of the pre-funded warrants purchased in the Private Placement. In addition, we agreed to use reasonable best efforts to cause such registration statement to be declared effective by the SEC on the earlier of (a) 60 days after the registration statement is filed or (b) 5 business days after the date we are notified (orally or in writing, whichever is earlier) by the SEC that the registration statement will not be “reviewed” or will not be subject to further review. The registration rights under the 2025 Registration Rights Agreement may be waived as to any purchaser. In November 2025, one purchaser waived its registration rights under the 2025 Registration Rights Agreement.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Stock Exchange Listing

Our common stock has been approved for listing on the Nasdaq Global Select Market under the ticker symbol “GRAL.”

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THE SELLING STOCKHOLDERS

This prospectus supplement relates to the proposed resale or other disposition from time to time of up to an aggregate of 3,925,767 shares of common stock by the selling stockholders, which consists of: (i) 1,927,194 shares of our common stock and (ii) 1,998,573 shares of our common stock issuable upon the exercise of pre-funded warrants to purchase shares of our common stock. We are registering the offer and sale of the shares covered by this prospectus supplement pursuant to the 2025 Registration Rights Agreement.

The following table sets forth information concerning the shares of common stock that may be offered from time to time by each of the selling stockholders. The number of shares beneficially owned by the selling stockholders is determined under rules issued by the SEC. Under these rules, beneficial ownership includes any shares as to which each of the selling stockholders has sole or shared voting power or investment power. Percentage ownership is based on 38,981,593 shares of common stock outstanding as of October 31, 2025, and, for each selling stockholder that owns securities that are exercisable or convertible into shares of common stock within 60 days of October 31, 2025, considers such shares of common stock outstanding, although these shares of common stock are not considered outstanding for purposes of computing the percentage ownership of any other selling stockholder.

For purposes of this table, we have assumed that the selling stockholders will have sold all of the shares of common stock covered by this prospectus supplement upon the completion of the offering (including all shares of common stock issuable upon exercise of pre-funded warrants relating to such shares).

The number of shares of our common stock offered for sale by the selling stockholders as set forth in the column below entitled “Number of Shares Offered” does not take into any contractual limitations contained in any securities, including the pre-funded warrants, that may restrict a holder (together with its affiliates) from beneficially owning in excess of a specified percentage of our common stock.

The information in the following table has been provided to us by or on behalf of the selling stockholders and the selling stockholders may have sold, transferred or otherwise disposed of all or a portion of the shares of common stock after the date on which they provided us with information regarding their securities. Each of the selling stockholders listed has sole voting and investment power with respect to the shares beneficially owned by the selling stockholder unless noted otherwise. The selling stockholders may sell all, some or none of its shares of common stock in this offering. See the section titled “Plan of Distribution.”

						Common Stock Beneficially Owned Before this Offering												Number of Shares Offered						Common Stock Beneficially Owned Upon Completion of this Offering
Selling Stockholder						Number						Percentage						Number						Number						Percentage
Entities affiliated with Baker Brothers Advisors LP(1)						1,961,728						4.99		%				1,427,552						1,630,125						4.18		%
Deep Track Biotechnology Master Fund, Ltd.(2)						927,909						2.38		%				927,909						—						—
Entities affiliated with Farallon Capital Management, L.L.C.(3)						2,006,684						5.07		%				571,021						1,435,663						3.68		%
RA Capital Healthcare Fund, L.P.(4)						428,266						1.10		%				428,266						—						—
Hims, Inc.(5)						285,510						*						285,510						—						—
Braidwell Partners Master Fund LP(6)						142,755						*						142,755						—						—
Perceptive Life Sciences Master Fund Ltd.(7)						142,754						*						142,754						—						—

__________________

*Less than 1%.

(1)Consists of (i) 138,344 shares of common stock held by 667, L.P. (“667”), (ii) 1,491,781 shares of common stock held by Baker Brothers Life Sciences, L.P. (“BBLS,” and, together with 667, the “Baker Funds”), and (iii) 331,603 shares of common stock issuable upon the exercise of pre-funded warrants held by BBLS. The amount reported prior to the offering excludes 1,095,949 shares of common stock issuable upon exercise of warrants held by the Baker Funds due to a beneficial ownership limitation contained in such securities that restrict the holder thereof (together with its affiliates) beneficially owning in excess of 4.99% of the common stock. Baker Bros. Advisors LP

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(“BBA”) is the management company and investment advisor to the Baker Funds and has sole voting and investment power with respect to the securities held by the Baker Funds. Baker Bros. Advisors (GP) LLC (“BBA-GP”) is the sole general partner of BBA. Julian C. Baker and Felix J. Baker are managing members of BBA-GP. BBA-GP, Felix J. Baker, Julian C. Baker and BBA may be deemed to be beneficial owners of the securities directly held by the Baker Funds. Julian C. Baker, Felix J. Baker, BBA and BBA-GP disclaim beneficial ownership of all securities held by the Baker Funds, except to the extent of their indirect pecuniary interest therein. The business address of each of the foregoing entities and persons is 860 Washington Street, 3rd Floor, New York, NY.

(2)Consists of 927,909 shares of common stock held by Deep Track Biotechnology Master Fund, Ltd. David Kroin is the managing member of Deep Track Capital GP, LLC, which is the general partner of Deep Track Capital, LP. Deep Track Capital, LP is the investment manager of Deep Track Biotechnology Master Fund, Ltd. David Kroin, Deep Track Capital GP, LLC, and Deep Track Capital, LP may be deemed to be beneficial owners of the securities directly held by Deep Track Biotechnology Master Fund Ltd. David Kroin, Deep Track Capital GP, LLC, and Deep Track Capital, LP disclaim beneficial ownership of all securities held by Deep Track Biotechnology Master Fund, Ltd., except to the extent of their indirect pecuniary interest therein. The address for each of the foregoing entities and persons is 200 Greenwich Ave, 3rd Floor, Greenwich, CT 06830.

(3)The securities covered by this prospectus supplement consist of an aggregate 571,021 shares of common stock issuable upon the exercise of pre-funded warrants held by the Farallon Funds (as defined below), as follows: (i) Farallon Capital Partners, L.P. (“FCP”) holds a pre-funded warrant exercisable for up to 27,452 shares of common stock; (ii) Farallon Capital Institutional Partners, L.P. (“FCIP”) holds a pre-funded warrant exercisable for up to 25,967 shares of common stock; (iii) Farallon Capital Institutional Partners II, L.P. (“FCIP II”) holds a pre-funded warrant exercisable for up to 8,151 shares of common stock; (iv) Farallon Capital Institutional Partners III, L.P. (“FCIP III”) holds a pre-funded warrant exercisable for up to 5,353 shares of common stock; (v) Four Crossings Institutional Partners V, L.P. (“FCIP V”) holds a pre-funded warrant exercisable for up to 6,752 shares of common stock; (vi) Farallon Capital Offshore Investors II, L.P. (“FCOI II”) holds a pre-funded warrant exercisable for up to 58,401 shares of common stock; (vii) Farallon Capital (AM) Investors, L.P. (“FCAMI”) holds a pre-funded warrant exercisable for up to 3,755 shares of common stock; (viii) Farallon Capital F5 Master I, L.P. (“F5MI”) holds a pre-funded warrant exercisable for up to 6,924 shares of common stock; and (ix) Farallon Healthcare Partners Master, L.P. (“FHPM” and, together with FCP, FCIP, FCIP II, FCIP III, FCIP V, FCOI II, FCAMI, and F5MI, the “Farallon Funds”) holds a pre-funded warrant exercisable for up to 428,266 shares of common stock. Farallon Partners, L.L.C. (the “Farallon General Partner”), as the general partner of each of FCP, FCIP, FCIP II, FCIP III, FCOI II and FCAMI and the sole member of the FCIP V General Partner and the FHPM General Partner (each as defined below), may be deemed a beneficial owner of the shares of common stock acquirable upon the exercise of the pre-funded warrants held by the Farallon Funds other than F5MI. Farallon Institutional (GP) V, L.L.C. (the “FCIP V General Partner”), as the general partner of FCIP V, may be deemed a beneficial owner of the shares of common stock acquirable upon the exercise of the pre-funded warrant held by FCIP V. Farallon F5 (GP), L.L.C. (the “F5MI General Partner”), as the general partner of F5MI, may be deemed a beneficial owner of the shares of common stock acquirable upon the exercise of the pre-funded warrant held by F5MI. Farallon Healthcare Partners (GP), L.L.C. (the “FHPM General Partner”), as the general partner of FHPM, may be deemed a beneficial owner of the shares of common stock acquirable upon the exercise of the pre-funded warrant held by FHPM. Each of Joshua J. Dapice, Philip D. Dreyfuss, Hannah E. Dunn, Richard B. Fried, Varun N. Gehani, Nicolas Giauque, David T. Kim, Michael G. Linn, Patrick (Cheng) Luo, Rajiv A. Patel, Dr. Thomas G. Roberts, Jr., Edric C. Saito, William Seybold, Daniel S. Short, Andrew J. M. Spokes, John R. Warren and Mark C. Wehrly (collectively, the “Farallon Managing Members”), as a senior managing member or managing member, as the case may be, of the Farallon General Partner, and a manager or senior manager, as the case may be, of the FCIP V General Partner, the F5MI General Partner, and the FHPM General Partner, in each case with the power to exercise investment discretion, may be deemed a beneficial owner of all such shares of common stock acquirable upon the exercise of the pre-funded warrants held by the Farallon Funds. Each of the Farallon General Partner, the FCIP V General Partner, the F5MI General Partner, the FHPM General Partner, and the Farallon Managing Members hereby disclaims any beneficial ownership of any such shares. In accordance with the beneficial ownership limitation set forth in the pre-funded warrants, no Farallon Fund may exercise a pre-funded warrant to the extent that immediately prior to or following such exercise, such Farallon Fund, together with any of its affiliates, persons that are members of a Section 13(d) group with it, and/or certain other attribution parties, beneficially owns or would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, in excess of 9.99% the shares of common stock that would be issued and outstanding immediately after giving effect to such exercise. The address of each of the entities and individuals referenced in this note is c/o Farallon Capital Management, L.L.C., One Maritime Plaza, Suite 2100, San Francisco, CA 94111.

(4)Consists of 428,266 shares of common stock held by RA Capital Healthcare Fund, L.P. RA Capital Management, L.P. is the investment manager for the RA Capital Healthcare Fund, L.P. The general partner of RA Capital Management, L.P. is RA Capital Management GP, LLC, of which Peter Kolchinsky and Rajeev Shah are the managing members. RA Capital Management, L.P., RA Capital Management GP, LLC, Mr. Kolchinsky and Mr. Shah may be deemed to be beneficial owners of the securities directly held by RA Capital Healthcare Fund, L.P. RA Capital Management, L.P., RA Capital Management GP, LLC, Mr. Kolchinsky and Mr. Shah disclaim beneficial ownership of all securities held by RA Capital Healthcare Fund, L.P, except to the extent of their indirect pecuniary interest therein. The business address of each of the foregoing entities and persons is 200 Berkeley St., 18 th Floor, Boston MA 02116.

(5)Consists of 285,510 shares of common stock held by Hims, Inc. Hims, Inc. is a Delaware corporation. The business address of Hims, Inc. is 2269 Chestnut Street, Suite 523, San Francisco, CA 94123.

(6)Consists of 142,755 shares of common stock held by Braidwell Partners Master Fund LP (“Braidwell Partners”). Braidwell LP (the “Braidwell Investment Manager”) is the investment manager of Braidwell Partners. Braidwell GP LLC (the “Braidwell GP”) is the general partner of Braidwell Partners. Braidwell Management LLC (the “Braidwell IM GP”) is the general partner of the Braidwell Investment Manager and the managing member of the Braidwell GP. Messrs. Alexander T. Karnal and Brian J. Kreiter (the “Co-Founders,” and together with Braidwell Partners, the Braidwell Investment Manager, the Braidwell GP and the Braidwell IM GP, the “Braidwell Parties”) together own, directly or indirectly, the Braidwell Investment Manager, the Braidwell GP and the Braidwell IM GP. The address of Braidwell Partners is c/o Maples Corporate Services Limited, P.O Box 309, Ugland House, Grand Cayman, KY1-1104 Cayman Islands. Each of the Braidwell Parties disclaims beneficial ownership of such shares except to the extent of any pecuniary interest therein. The principal address of the Braidwell Investment Manager, the Braidwell GP and the Co-Founders is One Harbor Point, 2200 Atlantic Street, 4th Floor, Stamford, Connecticut 06902.

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(7)Consists of 142,754 shares of common stock held by Perceptive Life Sciences Master Fund, Ltd. (“Perceptive Master Fund”). Excludes shares of common stock held by the Perceptive Master Fund that are not being registered hereby, and which represent less than 1% of the outstanding shares. Perceptive Advisors LLC ("Perceptive Advisors") is the investment advisor of the Perceptive Master Fund and may be deemed to have beneficial ownership of the shares beneficially owned thereby. Joseph Edelman is the controlling person of Perceptive Advisors and accordingly, may be deemed to have beneficial ownership of the shares beneficially owned by the Perceptive Master Fund and Perceptive Advisors. Perceptive Advisors, the Perceptive Master Fund and Mr. Edelman disclaim beneficial ownership of all such securities except to the extent of its or his pecuniary interest therein. The business address for each of Perceptive Advisors, the Perceptive Master Fund and Mr. Edelman is 51 Astor Place, 10th Floor, New York, NY 10003.

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PLAN OF DISTRIBUTION

The selling stockholders, which as used herein includes donees, pledgees, transferees or other successors-in-interest selling shares of common stock or interests in shares of common stock received after the date of this prospectus from a selling stockholder as a gift, pledge, partnership distribution or other transfer, may, from time to time, sell, transfer or otherwise dispose of any or all of their shares of common stock or interests in shares of common stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices.

The selling stockholders may use any one or more of the following methods when disposing of shares or interests therein:

•distributions to members, partners, stockholders or other equityholders of the selling stockholders;

•ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

•block trades in which the broker-dealer will attempt to sell the shares as agent, but may position and resell a portion of the block as principal to facilitate the transaction;

•purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

•an exchange distribution in accordance with the rules of the applicable exchange;

•privately negotiated transactions;

•short sales and settlement of short sales entered into after the effective date of the registration statement of which this prospectus is a part;

•through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise;

•broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share;

•a combination of any such methods of sale; and

•any other method permitted pursuant to applicable law.

The selling stockholders may, from time to time, pledge or grant a security interest in some or all of the shares of common stock owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock, from time to time, under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act, amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus. The selling stockholders also may transfer the shares of common stock in other circumstances, in which case the transferees, pledgees or other successors in interest will be the selling stockholders for purposes of this prospectus.

In connection with the sale of our common stock or interests therein, the selling stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the common stock in the course of hedging the positions they assume. The selling stockholders may also sell shares of our common stock short and deliver these securities to close out their short positions, or loan or pledge the common stock to broker-dealers that in turn may sell these securities. The selling stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).

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The aggregate proceeds to the selling stockholders from the sale of the common stock offered by them will be the purchase price of the common stock less discounts or commissions, if any. Each of the selling stockholders reserves the right to accept and, together with their agents from time to time, to reject, in whole or in part, any proposed purchase of common stock to be made directly or through agents. We will not receive any of the proceeds from this offering. Upon any exercise of the pre-funded warrants by payment of cash, however, we will receive the exercise price of the pre-funded warrants.

The selling stockholders also may resell all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act, provided that they meet the criteria and conform to the requirements of that rule, or another available exemption from the registration requirements under the Securities Act.

The selling stockholders and any underwriters, broker-dealers or agents that participate in the sale of the common stock or interests therein may be “underwriters” within the meaning of Section 2(a)(11) of the Securities Act (it being understood that the selling stockholders shall not be deemed to be underwriters solely as a result of their participation in this offering). Any discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions under the Securities Act. Selling stockholders who are “underwriters” within the meaning of Section 2(a)(11) of the Securities Act will be subject to the prospectus delivery requirements of the Securities Act.

To the extent required, the shares of our common stock to be sold, the names of the selling stockholders, the respective purchase prices and public offering prices, the names of any agent, dealer or underwriter, and any applicable commissions or discounts with respect to a particular offer will be set forth in an accompanying prospectus supplement or, if appropriate, a post-effective amendment to the registration statement that includes this prospectus.

In order to comply with the securities laws of some states, if applicable, the common stock may be sold in these jurisdictions only through registered or licensed brokers or dealers. In addition, in some states the common stock may not be sold unless it has been registered or qualified for sale or an exemption from registration or qualification requirements is available and is complied with.

We have advised the selling stockholders that the anti-manipulation rules of Regulation M under the Exchange Act may apply to sales of shares in the market and to the activities of the selling stockholders and their affiliates. In addition, to the extent applicable, we will make copies of this prospectus (as it may be supplemented or amended from time to time) available to the selling stockholders for the purpose of satisfying the prospectus delivery requirements of the Securities Act. The selling stockholders may indemnify any broker-dealer that participates in transactions involving the sale of the shares against certain liabilities, including liabilities arising under the Securities Act.

We have agreed to indemnify the selling stockholders against liabilities, including liabilities under the Securities Act and state securities laws, relating to the registration of the shares offered by this prospectus.

We have agreed with the selling stockholders to use commercially reasonable efforts to cause the registration statement of which this prospectus constitutes a part to become effective and to remain continuously effective until the earlier of: (i) the date on which the selling stockholders shall have resold or otherwise disposed of all the shares covered by this prospectus and (ii) the date on which the shares covered by this prospectus no longer constitute “Registrable Securities” as such term is defined in the Registration Rights Agreement, such that they may be resold by the selling stockholders without registration and without regard to any volume or manner-of-sale limitations and without current public information pursuant to Rule 144 under the Securities Act or any other rule of similar effect.

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LEGAL MATTERS

The validity of the shares of common stock being offered by this prospectus will be passed upon for us by Latham & Watkins LLP, Menlo Park, California. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2024, as set forth in their report, which is incorporated by reference in this prospectus supplement and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP's report, given on their authority as experts in accounting and auditing.

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WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE

Available Information

This prospectus supplement and the accompanying prospectus are part of the registration statement on Form S-3 we filed with the SEC under the Securities Act and do not contain all the information set forth in the registration statement. Whenever a reference is made in this prospectus supplement or the accompanying prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference in this prospectus supplement and the accompanying prospectus for a copy of such contract, agreement or other document. We file annual, quarterly and special reports, proxy statements and other information with the SEC. The SEC maintains a website that contains reports, proxy and information statements and other information about issuers, such as us, who file electronically with the SEC. The address of that website is www.sec.gov.

Incorporation by Reference

The SEC’s rules allow us to “incorporate by reference” information into this prospectus supplement, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus supplement, and subsequent information that we file with the SEC will automatically update and supersede that information. Any statement contained in this prospectus supplement or a previously filed document incorporated by reference will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement or a subsequently filed document incorporated by reference modifies or replaces that statement. Any such statement so modified or superseded shall not, except as so modified or superseded, constitute a part of this prospectus supplement and the accompanying prospectus.

This prospectus supplement incorporates by reference the documents set forth below that have previously been filed with the SEC (other than those documents or the portions of those documents not deemed to be filed):

•Our Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 5, 2025.

•The information specifically incorporated by reference into our Annual Report on Form 10-K from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 15, 2025.

•Our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2025, June 30, 2025 and September 30, 2025 filed with the SEC on May 14, 2025, August 13, 2025 and November 13, 2025, respectively.

•Our Current Reports on Form 8-K filed with the SEC on May 16, 2025, May 30, 2025, September 18, 2025, October 16, 2025 and October 20, 2025.

•The description of our common stock, contained in our registration statement on Form 10 filed on May 6, 2024 and any amendment or report filed with the SEC for the purpose of updating the description, including Exhibit 4.1 to our Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 5, 2025.

We are also incorporating by reference additional documents that we may file with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus supplement and prior to the completion of the offering contemplated hereby, but excluding any information furnished to, rather than filed with, the SEC.

Upon request, we will provide, without charge, to each person, including any beneficial owner, to whom a copy of this prospectus supplement and the accompanying prospectus is delivered, a copy of the documents incorporated by reference into this prospectus supplement. You may request a copy of these filings, and any exhibits we have

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specifically incorporated by reference as an exhibit in this prospectus supplement and the accompanying prospectus, at no cost by writing or telephoning us at the following:

GRAIL, Inc.

1525 O’Brien Drive

Menlo Park, California 94025

(833) 694-2553

You may also access these filings and documents free of charge on the SEC’s website at www.sec.gov or on the “Investors” page of our website at www.grail.com. Other than such documents, information contained on our website is not incorporated by reference into this prospectus supplement and the accompanying prospectus, and you should not consider any information on, or that can be accessed from, our website as part of this prospectus supplement or the accompanying prospectus.

This prospectus supplement and the accompanying prospectus is part of a registration statement we filed with the SEC. We have incorporated exhibits into this registration statement. You should read the exhibits carefully for provisions that may be important to you.

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PROSPECTUS

GRAIL, INC.

Common Stock

Preferred Stock

Debt Securities

Warrants

Purchase Contracts

Units

Subscription Rights

Common Stock

Offered by the Selling Securityholders

We may offer and sell the securities identified above, and the selling securityholders may offer and sell shares of common stock, in each case from time to time in one or more offerings. This prospectus provides you with a general description of the securities. We will not receive any proceeds from the sale of our common stock by the selling securityholders.

Each time we offer and sell securities, we will provide a supplement to this prospectus that contains specific information about the offering and the amounts, prices and terms of the securities. In addition, in connection with certain offers and sales of securities by the selling securityholders, we and the selling securityholders will provide, if applicable, a prospectus supplement to this prospectus containing specific information about the offering by the selling securityholders and the amounts, prices and terms of the securities being offered. The supplement may also add, update or change information contained in, or incorporated by reference into, this prospectus with respect to that offering. You should carefully read this prospectus and the applicable prospectus supplement before you invest in any of our securities.

We may offer and sell the securities described in this prospectus and any prospectus supplement to or through one or more underwriters, dealers and agents, or directly to purchasers, or through a combination of these methods. In addition, the selling securityholders may offer and sell shares of our common stock from time to time, together or separately. If any underwriters, dealers or agents are involved in the sale of any of the securities, their names and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement. See the sections of this prospectus titled “About this Prospectus” and “Plan of Distribution” for more information. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such securities.

INVESTING IN OUR SECURITIES INVOLVES RISKS. SEE THE “RISK FACTORS” ON PAGE 6 OF THIS PROSPECTUS AND ANY SIMILAR SECTION CONTAINED IN THE APPLICABLE PROSPECTUS SUPPLEMENT CONCERNING FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN OUR SECURITIES.

Our common stock is listed on the Nasdaq Global Select Market under the symbol “GRAL.” On November 12, 2025, the last reported sale price of our common stock on the Nasdaq Global Select Market was $84.77 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is November 13, 2025.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS			1
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			2
WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE			3
THE COMPANY			5
RISK FACTORS			6
USE OF PROCEEDS			7
DESCRIPTION OF CAPITAL STOCK			8
DESCRIPTION OF DEBT SECURITIES			15
DESCRIPTION OF OTHER SECURITIES			23
GLOBAL SECURITIES			24
SELLING SECURITYHOLDERS			28
PLAN OF DISTRIBUTION			29
LEGAL MATTERS			30
EXPERTS			30

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the U.S. Securities and Exchange Commission (the “SEC”) as a “well-known seasoned issuer” (as such term is defined in Rule 405 under the Securities Act of 1933, as amended (the “Securities Act”)) using a “shelf” registration process.

By using a shelf registration statement, we may sell securities from time to time and in one or more offerings, and the selling securityholders to be named in a supplement to this prospectus may sell shares of common stock from time to time in one or more offerings, as described in this prospectus. Each time that we or the selling securityholders offer and sell securities, we or the selling securityholders will provide a prospectus supplement to this prospectus that contains specific information about the securities being offered and sold and the specific terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement or free writing prospectus may also add, update or change information contained in, or incorporated by reference into, this prospectus with respect to that offering. If there is any inconsistency between the information in this prospectus and any applicable prospectus supplement or free writing prospectus, you should rely on the prospectus supplement or free writing prospectus, as applicable. Before purchasing any securities, you should carefully read both this prospectus and the applicable prospectus supplement or any free writing prospectus, together with the additional information described under the heading “Where You Can Find More Information; Incorporation by Reference” in this prospectus.

Neither we, nor the selling securityholders, have authorized anyone to provide you with any information or to make any representations other than those contained in, or incorporated by reference into, this prospectus, any applicable prospectus supplement or any free writing prospectuses prepared by or on behalf of us or to which we have referred you. We and the selling securityholders take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We and the selling securityholders will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus and the applicable prospectus supplement to this prospectus is accurate only as of the date on its respective cover, that the information appearing in any applicable free writing prospectus is accurate only as of the date of that free writing prospectus, and that any information incorporated by reference is accurate only as of the date of the document incorporated by reference, unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates. This prospectus incorporates by reference, and any prospectus supplement or free writing prospectus may contain and incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, we do not guarantee the accuracy or completeness of this information and we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus, any prospectus supplement or any applicable free writing prospectus may involve estimates, assumptions and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading “Risk Factors” contained in this prospectus, the applicable prospectus supplement and any applicable free writing prospectus, and under similar headings in other documents that are incorporated by reference into this prospectus. Accordingly, investors should not place undue reliance on this information.

When we refer to “GRAIL,” “we,” “our,” “us,” “our company” and the “Company” in this prospectus, we mean GRAIL, Inc. and its consolidated subsidiaries, unless otherwise specified. When we refer to “you,” we mean the potential holders of the applicable series of securities.

“GRAIL,” the GRAIL logos, “Galleri” and other trade names, trademarks or service marks of GRAIL appearing in this prospectus and any applicable prospectus supplement or applicable free writing prospectus are the property of GRAIL. GRAIL also owns or has the rights to copyrights that protect the content of its products. Other trade names, trademarks, service marks or copyrights appearing in, or incorporated by reference into, this prospectus or any applicable prospectus supplement or applicable free writing prospectus are the property of their respective holders. Solely for convenience, trade names, trademarks, service marks, and copyrights referred to in this prospectus appear without the ®, ™, SM, and © symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or that the applicable owner will not assert its rights, to these trade names, trademarks, service marks, and copyrights.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus contains, and the information incorporated by reference herein and any applicable prospectus supplement may contain, “forward-looking statements” within the meaning of Section 27A of the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which statements involve substantial risks and uncertainties. All statements contained or incorporated by reference herein other than statements of historical fact are forward-looking statements. In some cases, you can identify these statements by forward-looking words such as “aim,” “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “potential,” “predict,” “should,” “would,” or “will,” the negative of these terms, and other comparable terminology, but the absence of these words does not mean that a statement is not forward looking. These forward-looking statements, which are subject to risks, uncertainties, and assumptions about us, may include expectations and projections of our future financial performance, future tests or products, technology, clinical studies, regulatory landscape, compliance and strategy, potential market opportunity, anticipated growth strategies, sufficiency of cash on hand to finance our business, cost savings, budgets and strategies, restructuring and stock-based compensation costs, impact of the restructuring on our operations and anticipated trends in our business.

These statements are only predictions based on our current expectations and projections about future events and trends. There are important factors that could cause our actual results, level of activity, performance, or achievements to differ materially and adversely from those expressed or implied by the forward-looking statements, including those factors discussed under the sections titled “Risk Factors” in this prospectus and the risks discussed in our other SEC filings. You should specifically consider the numerous risks described under these sections. Moreover, we operate in a dynamic and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results, level of activity, performance, or achievements to differ materially and adversely from those contained in any forward-looking statements we may make.

Forward-looking statements relate to the future and, accordingly, are subject to inherent uncertainties, risks, and changes in circumstances that are difficult to predict and many of which are outside of our control. Although we believe the expectations and projections expressed or implied by the forward-looking statements are reasonable, we cannot guarantee future results, level of activity, performance, or achievements. Our actual results and financial condition may differ materially from those indicated in the forward-looking statements. Except to the extent required by law, we undertake no obligation to update any of these forward-looking statements after the date of this prospectus supplement to conform our prior statements to actual results or revised expectations or to reflect new information or the occurrence of unanticipated events.

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WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE

Available Information

We file reports, proxy statements and other information with the SEC. The SEC maintains a website that contains reports, proxy and information statements and other information about issuers, such as us, who file electronically with the SEC. The address of that website is http://www.sec.gov.

Our website address is www.grail.com. The information on or accessible through our website, however, is not, and should not be deemed to be, a part of this prospectus or any prospectus supplement. We have included our website address as an inactive textual reference only.

This prospectus and any prospectus supplement are part of a registration statement that we filed with the SEC and do not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided below. Forms of the indenture and other documents establishing the terms of the offered securities are or may be filed as exhibits to the registration statement or documents incorporated by reference in the registration statement. Statements in this prospectus or any prospectus supplement about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC’s website, as provided above.

Incorporation by Reference

The SEC’s rules allow us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus, and subsequent information that we file with the SEC will automatically update and supersede that information. Any statement contained in this prospectus or a previously filed document incorporated by reference will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or a subsequently filed document incorporated by reference modifies or replaces that statement.

This prospectus and any accompanying prospectus supplement incorporate by reference the documents set forth below that have previously been filed with the SEC:

•Our Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 5, 2025.

•The information specifically incorporated by reference into our Annual Report on Form 10-K from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 15, 2025.

•Our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2025, June 30, 2025 and September 30, 2025 filed with the SEC on May 14, 2025, August 13, 2025 and November 13, 2025, respectively.

•Our Current Reports on Form 8-K filed with the SEC on May 16, 2025, May 30, 2025, September 18, 2025, October 16, 2025 and October 20, 2025.

•The description of our common stock contained in our registration statement on Form 10 filed on May 6, 2024 and any amendment or report filed with the SEC for the purpose of updating the description, including Exhibit 4.1 to our Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 5, 2025.

All reports and other documents we subsequently file pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, prior to the termination of this offering but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus and deemed to be part of this prospectus from the date of the filing of such reports and documents.

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You may request a free copy of any of the documents incorporated by reference in this prospectus by writing or telephoning us at the following address:

GRAIL, Inc.

1525 O’Brien Drive

Menlo Park, California 94025

(833) 694-2553

Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference in this prospectus or any accompanying prospectus supplement.

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THE COMPANY

We are an innovative commercial-stage healthcare company focused on saving lives and shifting the paradigm in early cancer detection. We believe screening individuals for many types of cancer with a single test represents a significant opportunity to reduce the global burden of cancer. Our Galleri test is a commercially available screening test for early detection of multiple types of cancer, which we termed multi-cancer early detection. We believe Galleri is clinically validated based on the results of its clinical studies completed to date, including the results of its foundational case-control Circulating Cell-free Genome Atlas study, interventional PATHFINDER study, data from the NHS-Galleri prevalent screening round and initial data the PATHFINDER 2 study. In these studies, Galleri demonstrated an ability to detect a shared cancer signal across multiple types of cancer, accurately predict the specific organ or tissue type where the cancer signal originated, and yield high positive predictive values and low false positive rates, all from a simple blood draw.

Galleri results can help guide next steps for diagnosis of cancer by healthcare providers in required follow-up diagnostic testing. We launched Galleri in the United States in mid-2021. Galleri has detected some of the most aggressive cancers in early stages including, among others, endometrial, esophageal, gastric, head and neck, liver, pancreatic, and rectal cancers.

We were incorporated in the State of Delaware in connection with the conversion of GRAIL, LLC, a Delaware limited liability company, to GRAIL, Inc., on June 21, 2024. Our principal executive offices are located at 1525 O’Brien Drive, Menlo Park, California 94025, and our telephone number is (833) 694-2553.

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RISK FACTORS

Investment in any securities offered pursuant to this prospectus and the applicable prospectus supplement involves risks. Before deciding whether to invest in our securities, you should carefully consider the risk factors incorporated by reference to our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in the applicable prospectus supplement and any applicable free writing prospectus. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our securities to decline, resulting in a loss of all or part of your investment. Please also carefully read the section titled “Cautionary Note Regarding Forward-Looking Statements” included in our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K.

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USE OF PROCEEDS

We intend to use the net proceeds from the sale of the securities as set forth in the applicable prospectus supplement. We will not receive any of the proceeds from the sale of common stock being offered by any of the selling securityholders.

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DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock is not complete and may not contain all the information you should consider before investing in our capital stock. This description is summarized from, and qualified in its entirety by reference to, our certificate of incorporation (“Certificate of Incorporation”), our amended and restated bylaws (“Bylaws”) and the agreements to which we and certain of our stockholders are parties, each of which are incorporated by reference as exhibits to the registration statement of which this prospectus forms a part, and by applicable law. We encourage you to read our Certificate of Incorporation, our Bylaws, our Stockholder and Registration Rights Agreement (as defined below) and our 2025 Registration Rights Agreement (as defined below), each of which has been publicly filed with the SEC, and the applicable provisions of Delaware law, for more information. See “Where You Can Find More Information; Incorporation by Reference.”

Our authorized capital stock consists of:

•1,500,000,000 shares of common stock, par value $0.001 per share; and

•50,000,000 shares of preferred stock, par value $0.001 per share.

Common Stock

Dividend Rights. Holders of shares of our common stock are entitled to receive dividends when, as and if declared by our Board of Directors (“Board”) at its discretion out of funds legally available for that purpose, subject to the preferential rights of any preferred stock that may be outstanding.

Voting Rights. Each share of common stock is entitled to one vote upon any matter submitted to a vote of our stockholders, including the election of directors. Holders of our common stock vote as a single class on all matters submitted to a stockholder vote, subject to any voting rights granted to holders of any preferred stock. Holders of the common stock are not entitled to any cumulative voting rights. Except as otherwise provided by the Certificate of Incorporation, the Bylaws, the rules or regulations of any stock exchange applicable to the Company, or applicable law or pursuant to any regulation applicable to the Company or its securities, each matter (other than the election of directors, as described below under “—Election and Removal of Directors; Vacancies”) presented to the stockholders at a duly called or convened meeting at which a quorum is present shall be decided by the affirmative vote of the holders of a majority in voting power of the votes cast (excluding abstentions and broker non-votes) on such matter.

Liquidation. In the event of our liquidation, dissolution, or winding up, the holders of common stock are entitled to share ratably in all assets remaining after payment of liabilities, subject to prior distribution rights of preferred stock, if any, then outstanding.

Other Rights. The holders of our common stock have no preemptive rights or other subscription rights.

There are no redemption or sinking fund provisions applicable to our common stock.

Preferred Stock

Our Board has the authority to issue the preferred stock in one or more series and to fix the rights, preferences, privileges, and restrictions thereof, including dividend rights, dividend rates, conversion rights, voting rights, terms of redemption, redemption prices, liquidation preferences, and the number of shares constituting any series or the designation of such series, without further vote or action by the stockholders. The issuance of preferred stock may have the effect of delaying, deterring, or preventing a change in control of our company without further action by the stockholders and may adversely affect the voting and other rights of the holders of common stock.

Pre-Funded Warrants

In October 2025, we entered into a securities purchase agreement with certain purchasers, pursuant to which we agreed to sell securities to such purchasers in a private placement. In connection with the private placement, we issued and sold, in lieu of shares of our common stock for certain purchasers, pre-funded warrants to purchase

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1,998,573 shares of our common stock at a public offering price of $70.049 per underlying share of common stock, with an exercise price of $0.001 per underlying share of common stock. The pre-funded warrants are exercisable at any time.

The exercise price and number of shares of our common stock issuable upon exercise of the pre-funded warrants may be adjusted upon the occurrence of specific events, including stock dividends, stock splits, reclassifications and combinations of our common stock.

The holders of the pre-funded warrants must pay the exercise price upon exercise of the pre-funded warrants, unless such holders are utilizing the cashless exercise provision of the pre-funded warrants. The pre-funded warrants may be exercised at such time by means of a “cashless exercise” in which, in lieu of making the cash payment otherwise contemplated to be made to us upon such exercise in payment of the aggregate exercise price, the holder may elect instead to receive upon such exercise the net number of shares of common stock determined according to a formula set forth in the pre-funded warrants.

In the event of certain fundamental transactions (as described in the pre-funded warrants), a holder of pre-funded warrants will be entitled to receive, upon exercise of the pre-funded warrants, the kind and amount of securities, cash or other property that such holder would have received had they exercised the pre-funded warrants immediately prior to such fundamental transaction without regard to any limitations on exercise contained in the pre-funded warrants.

Except for the right to participate in certain dividends and distributions and as otherwise provided in the pre-funded warrants or by virtue of a holder’s ownership of our common stock, the holders of pre-funded warrants do not have the rights or privileges of holders of our common stock, including any voting rights, until they exercise their warrants.

Certain Provisions of Delaware Law, Our Certificate of Incorporation and Bylaws

Election and Removal of Directors; Vacancies

Our Board consists of between five and fifteen directors. The exact number of directors is fixed from time to time by resolution of the Board. Directors are elected by a plurality of the votes of the shares of our capital stock present in person or represented by proxy at the meeting and entitled to vote on the election of directors.

No director may be removed except for cause, and directors may be removed for cause only by an affirmative vote of shares representing not less than a majority of the shares then entitled to vote at an election of directors.

Any vacancy occurring on the Board and any newly created directorship may be filled only by a majority of the remaining directors in office.

Staggered Board

Our Board is divided into three classes serving staggered three-year terms. At each annual meeting of stockholders, directors are elected to succeed the class of directors whose terms have expired. This classification of our Board could have the effect of increasing the length of time necessary to change the composition of a majority of the Board. In general, at least two annual meetings of stockholders will typically be necessary for stockholders to effect a change in a majority of the members of the Board.

Limitation on Action by Written Consent

Our Certificate of Incorporation and our Bylaws provide that holders of our common stock are not able to act by written consent without a meeting.

Stockholder Meetings

Our Certificate of Incorporation and our Bylaws provide that special meetings of our stockholders may be called only at the direction of the Chief Executive Officer, the Board, or the Chairperson of the Board or the Lead

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Independent Director. Our Certificate of Incorporation and our Bylaws specifically deny any power of any other person to call a special meeting.

Amendment of Certificate of Incorporation

The provisions of our Certificate of Incorporation described under “—Election and Removal of Directors; Vacancies,” “—Stockholder Meetings,” “—Limitation on Action by Written Consent,” “—Limitation of Liability of Directors and Officers,” “—Common Stock-Voting Rights,” and “—Forum Selection” and provisions relating to amendments to our Certificate of Incorporation may be amended only by the affirmative vote of holders of at least 66-2/3% of the voting power of our outstanding shares of voting stock. The affirmative vote of holders of at least a majority of the voting power of our outstanding shares of stock is generally required to amend other provisions of our Certificate of Incorporation.

Amendment of Bylaws

Certain provisions of our Bylaws may generally be altered, amended, or repealed, and new bylaws may be adopted, with the affirmative vote of a majority of directors present at any regular or special meeting of the Board called for that purpose, provided that any alteration, amendment, or repeal of, or adoption of any bylaw inconsistent with specified provisions of the bylaws, including those related to special and annual meetings of stockholders, action of stockholders by written consent, nomination of directors, transfers of capital stock and dividends requires the affirmative vote of at least 66-2/3% of all directors in office at a meeting called for that purpose.

All other provisions of our Bylaws may generally be altered, amended, or repealed, and new bylaws may be adopted, with the affirmative vote of holders of 66-2/3% of the voting power of our outstanding shares of voting stock.

Other Limitations on Stockholder Actions

Our Bylaws impose some procedural requirements on stockholders who wish to:

•make nominations in the election of directors;

•propose that a director be removed;

•propose any repeal or change in our Bylaws; or

•propose any other business to be brought before an annual or special meeting of stockholders.

Under these procedural requirements, in order to bring a proposal before a meeting of stockholders, a stockholder must deliver timely notice of a proposal pertaining to a proper subject for presentation at the meeting to our corporate secretary along with the following:

•a description of the business or nomination to be brought before the meeting and the reasons for conducting such business at the meeting;

•the stockholder’s name and address;

•any material interest of the stockholder in the proposal;

•the number of shares beneficially owned by the stockholder and evidence of such ownership; and

•the names and addresses of all persons with whom the stockholder is acting in concert and a description of all arrangements and understandings with those persons, and the number of shares such persons beneficially own.

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To be timely, a stockholder must generally deliver notice:

•in connection with an annual meeting of stockholders, not less than 90 nor more than 120 days prior to the date on which the annual meeting of stockholders was held in the immediately preceding year, but in the event that the date of the annual meeting is more than 30 days before or more than 60 days after the anniversary date of the preceding annual meeting of stockholders, a stockholder notice will be timely if received by us no later than the 120 days prior to such annual meeting and not later than (i) 90 days prior to the date of the annual meeting or, if later, (2) the 10th day following the day on which we first publicly announce the date of the annual meeting; or

•in connection with the election of a director at a special meeting of stockholders, during the period not less than 90 nor more than 120 days prior to the date of the special meeting, or the 10th day following the day on which a notice of the date of the special meeting was mailed to the stockholders or the public disclosure of that date was made.

In order to submit a nomination for our Board, a stockholder must also submit all information with respect to the nominee that would be required to be included in a proxy statement, as well as other information. If a stockholder fails to follow the required procedures, the stockholder’s proposal or nominee will be ineligible and will not be voted on by our stockholders.

Indemnification of Directors and Officers and Limitation of Liability of Directors and Officers

Section 145 of the Delaware General Corporation Law provides that a corporation may indemnify directors and officers as well as other employees and agents against expenses (including attorneys’ fees), judgments, fines, and amounts paid in settlement actually and reasonably incurred by such person in connection with any threatened, pending, or completed actions, suits, or proceedings in which such person is made a party by reason of such person being or having been a director, officer, employee, or agent to the registrant. The Delaware General Corporation Law provides that Section 145 is not exclusive of other rights to which those seeking indemnification may be entitled under any bylaw, agreement, vote of stockholders or disinterested directors or otherwise.

Our Certificate of Incorporation provides that, to the fullest extent permitted by law, we will indemnify any officer or director of our company against all damages, claims, and liabilities arising out of the fact that the person is or was our director or officer, or served any other enterprise at our request as a director or officer. Amending this provision will not reduce our indemnification obligations relating to actions taken before an amendment. GRAIL has entered into indemnification agreements with each of its current directors, executive officers, and certain other officers to provide these directors and officers additional contractual assurances regarding the scope of the indemnification set forth in our Certificate of Incorporation and our Bylaws and to provide additional procedural protections. There is no pending litigation or proceeding involving a director or executive officer of GRAIL for which indemnification has been sought.

Our Certificate of Incorporation also provides that no director or officer will be personally liable to us or our stockholders for monetary damages for breach of fiduciary duty as a director or officer, except as required by applicable law, as in effect from time to time. Section 102(b)(7) of the Delaware General Corporation Law permits a corporation to provide in its certificate of incorporation that a director or officer of the corporation shall not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director or officer, except for liability of:

•a director or officer for any breach of the director’s or officer’s duty of loyalty to our company or our stockholders;

•a director or officer for any act or omission not in good faith or which involved intentional misconduct or a knowing violation of law;

•a director for unlawful payments of dividends or unlawful stock repurchases or redemptions as provided in Section 174 of the Delaware General Corporation Law;

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•a director or officer for any transaction from which the director or officer derived an improper personal benefit; and

•an officer in any action by or in the right of our company.

As a result, neither we nor our stockholders have the right, through stockholders’ derivative suits on our behalf, to recover monetary damages against a director or officer for breach of fiduciary duty as a director or officer, including breaches resulting from grossly negligent behavior, except in the situations described above.

Forum Selection

Our Certificate of Incorporation provides that the Court of Chancery of the State of Delaware is the sole and exclusive forum for the following types of actions or proceedings under Delaware statutory or common law: (i) any derivative action or proceeding brought on behalf of us; (ii) any action asserting a claim of breach of fiduciary duty owed by any director, officer, or other employee of our company to us or our stockholders; (iii) any action asserting a claim arising pursuant to any provision of the Delaware General Corporation Law or our Certificate of Incorporation and bylaws; or (iv) any action asserting a claim governed by the internal affairs doctrine. This provision would not apply to claims brought to enforce a duty or liability created by the Securities Exchange Act of 1934, as amended, or any other claim for which the federal courts have exclusive jurisdiction. Furthermore, our Certificate of Incorporation also provides that unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States shall be the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act of 1933, as amended. Any person or entity purchasing or otherwise acquiring any interest in our shares of capital stock shall be deemed to have notice of and have consented to the foregoing forum selection provisions.

Our exclusive forum provision does not relieve us of our duties to comply with the federal securities laws and the rules and regulations thereunder, and our stockholders will not be deemed to have waived our compliance with these laws, rules and regulations.

The enforceability of similar federal court choice of forum provisions in other companies’ certificates of incorporation has been challenged in legal proceedings, and it is possible that a court could find this type of provision to be inapplicable or unenforceable. If a court were to find either of the choice of forum provisions contained in our Certificate of Incorporation or Bylaws to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions.

The choice of forum provisions may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with the company or its directors, officers or other employees, which may discourage such lawsuits against the company and its directors, officers, and other employees and result in increased costs for investors to bring a claim.

Delaware Business Combination Statute

We have elected to be subject to Section 203 of the Delaware General Corporation Law. Section 203 prevents an “interested stockholder,” which is defined generally as a person owning 15% or more of a corporation’s voting stock, or any affiliate or associate of that person, from engaging in a broad range of “business combinations” with the corporation for three years after becoming an interested stockholder unless:

•the Board of the corporation had previously approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;

•upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, that person owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, other than statutorily excluded shares; or

•following the transaction in which that person became an interested stockholder, the business combination is approved by the Board of the corporation and holders of at least two-thirds of the outstanding voting stock not owned by the interested stockholder.

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Under Section 203, the restrictions described above also do not apply to specific business combinations proposed by an interested stockholder following the announcement or notification of designated extraordinary transactions involving the corporation and a person who had not been an interested stockholder during the previous three years or who became an interested stockholder with the approval of a majority of the corporation’s directors, if such extraordinary transaction is approved or not opposed by a majority of the directors who were directors prior to any person becoming an interested stockholder during the previous three years or were recommended for election or elected to succeed such directors by a majority of such directors.

Section 203 may make it more difficult for a person who would be an interested stockholder to effect various business combinations with a corporation for a three-year period. Section 203 also may have the effect of preventing changes in our management and could make it more difficult to accomplish transactions that our stockholders may otherwise deem to be in their best interests.

Anti-Takeover Effects of Some Provisions

Certain provisions of our Certificate of Incorporation and Bylaws could make the following more difficult:

•acquisition of control of us by means of a proxy contest, tender offer, or otherwise; or

•removal of our incumbent officers and directors.

These provisions, as well as our ability to issue preferred stock, are designed to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with our Board. We believe that the benefits of increased protection give us the potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us, and that the benefits of this increased protection outweigh the disadvantages of discouraging those proposals, because negotiation of those proposals could result in an improvement of their terms.

Stockholder and Registration Rights Agreement

We and Illumina, Inc. (“Illumina”) are parties to a stockholder and registration rights agreement (the “Stockholder and Registration Rights Agreement”) pursuant to which we granted to Illumina certain registration rights with respect to the shares of our common stock owned by Illumina. Illumina may transfer these rights in certain limited circumstances, including in connection with an equity-for-debt exchange to a third-party lender (a “Permitted Transferee” and, collectively with Illumina, “Holders”), and such Holders will thereafter be bound by the terms of the Stockholder and Registration Rights Agreement.

Demand Registration

Holders are able to request registration under the Securities Act of all or any portion of their shares of our common stock covered by the Stockholder and Registration Rights Agreement, and we are obligated, subject to limitations on minimum offering size and certain other limited exceptions, to register such shares as requested by such Holders. Holders are generally able to designate the terms of each offering effected pursuant to a demand registration, which may take the form of a shelf registration, and are able to request that we complete up to three demand registrations in any 12-month period, provided that we shall not be obligated to effect more than five demand registration in the aggregate.

We are not required to honor a demand registration if we have effected a registration within the preceding 60 days. In addition, if we reasonably determine in good faith that filing a registration statement would be significantly disadvantageous to us, we may, no more than twice during any 12-month period, delay filing such registration statement until the earlier of 90 days after we make such determination or seven days after the disadvantageous condition no longer exists, provided that these postponement rights shall not be applicable to the Holders for more than a total of 120 days during any 12-month period.

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Piggy-Back Registration

If we at any time intend to file on our behalf or on behalf of any of our other security holders a registration statement in connection with a public offering of any of our securities on a form and in a manner that would permit the registration for offer and sale of shares of our common stock held by Holders, Holders have the right to include their shares of our common stock in that offering, subject to certain limitations.

Indemnification

The Stockholder and Registration Rights Agreement contains customary indemnification and contribution provisions by us for the benefit of Holders and, in limited situations, by Holders for the benefit of us with respect to the information provided by such Holders included in any registration statement, prospectus, or related document.

Voting Restrictions

Illumina agreed to vote any shares of our common stock that it retains in proportion to the votes cast by our other stockholders and granted us a proxy to vote its shares of our common stock in such proportion. Any such proxy, however, will be automatically revoked as to a particular share upon any sale or transfer of such share from Illumina to a person other than Illumina, and neither the Stockholder and Registration Rights Agreement nor proxy limits or prohibits any such sale or transfer.

2025 Registration Rights Agreement

We and certain investors are party to a registration rights agreement (the “2025 Registration Rights Agreement”), pursuant to which we granted the purchasers of our common stock and pre-funded warrants to purchase shares of our common stock certain registration rights. We entered into the 2025 Registration Rights Agreement in connection with the issuance and sale by us of 2,640,970 shares of our common stock and pre-funded warrants to purchase 1,998,573 shares of our common stock in a private placement to certain investors, which closed on October 21, 2025 (the “Private Placement”).

Pursuant to the 2025 Registration Rights Agreement, we agreed to prepare and file a registration statement with the SEC within 30 days after the closing date of the Private Placement for purposes of registering the resale of the shares of our common stock and the shares of our common stock issuable upon exercise of the pre-funded warrants purchased in the Private Placement. In addition, we agreed to use reasonable best efforts to cause such registration statement to be declared effective by the SEC on the earlier of (a) 60 days after the registration statement is filed or (b) 5 business days after the date we are notified (orally or in writing, whichever is earlier) by the SEC that the registration statement will not be “reviewed” or will not be subject to further review.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Stock Exchange Listing

Our common stock has been approved for listing on the Nasdaq Global Select Market under the ticker symbol “GRAL.”

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DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplement or free writing prospectus, summarizes certain general terms and provisions of the debt securities that we may offer under this prospectus. When we offer to sell a particular series of debt securities, we will describe the specific terms of the series in a supplement to this prospectus. We will also indicate in the supplement to what extent the general terms and provisions described in this prospectus apply to a particular series of debt securities.

We may issue debt securities either separately, or together with, or upon the conversion or exercise of or in exchange for, other securities described in this prospectus. Debt securities may be our senior, senior subordinated or subordinated obligations and, unless otherwise specified in a supplement to this prospectus, the debt securities will be our direct, unsecured obligations and may be issued in one or more series.

The debt securities will be issued under an indenture between us and Wilmington Trust, National Association, as trustee. We have summarized select portions of the indenture below. The summary is not complete. The form of the indenture has been filed as an exhibit to the registration statement of which this prospectus forms a part and you should read the indenture for provisions that may be important to you. In the summary below, we have included references to the section numbers of the indenture so that you can easily locate these provisions. Capitalized terms used in the summary and not defined herein have the meanings specified in the indenture.

As used in this section only, “GRAIL,” “we,” “our” or “us” refer to GRAIL, Inc. excluding our subsidiaries, unless expressly stated or the context otherwise requires.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of our board of directors and set forth or determined in the manner provided in a resolution of our board of directors, in an officer’s certificate or by a supplemental indenture. (Section 2.2) The particular terms of each series of debt securities will be described in a prospectus supplement relating to such series (including any pricing supplement or term sheet).

We can issue an unlimited amount of debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium, or at a discount. (Section 2.1) We will set forth in a prospectus supplement (including any pricing supplement or term sheet) relating to any series of debt securities being offered, the aggregate principal amount and the following terms of the debt securities, if applicable:

•the title and ranking of the debt securities (including the terms of any subordination provisions);

•the price or prices (expressed as a percentage of the principal amount) at which we will sell the debt securities;

•any limit on the aggregate principal amount of the debt securities;

•the date or dates on which the principal of the securities of the series is payable;

•the rate or rates (which may be fixed or variable) per annum or the method used to determine the rate or rates (including any commodity, commodity index, stock exchange index or financial index) at which the debt securities will bear interest, the date or dates from which interest will accrue, the date or dates on which interest will commence and be payable and any regular record date for the interest payable on any interest payment date;

•the place or places where principal of, and interest, if any, on the debt securities will be payable (and the method of such payment), where the securities of such series may be surrendered for registration of transfer or exchange, and where notices and demands to us in respect of the debt securities may be delivered;

•the period or periods within which, the price or prices at which and the terms and conditions upon which we may redeem the debt securities;

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•any obligation we have to redeem or purchase the debt securities pursuant to any sinking fund or analogous provisions or at the option of a holder of debt securities and the period or periods within which, the price or prices at which and in the terms and conditions upon which securities of the series shall be redeemed or purchased, in whole or in part, pursuant to such obligation;

•the dates on which and the price or prices at which we will repurchase debt securities at the option of the holders of debt securities and other detailed terms and provisions of these repurchase obligations;

•the denominations in which the debt securities will be issued, if other than denominations of $1,000 and any integral multiple thereof;

•whether the debt securities will be issued in the form of certificated debt securities or global debt securities;

•the portion of principal amount of the debt securities payable upon declaration of acceleration of the maturity date, if other than the principal amount;

•the currency of denomination of the debt securities, which may be U.S. Dollars or any foreign currency, and if such currency of denomination is a composite currency, the agency or organization, if any, responsible for overseeing such composite currency;

•the designation of the currency, currencies or currency units in which payment of principal of, premium and interest on the debt securities will be made;

•if payments of principal of, premium or interest on the debt securities will be made in one or more currencies or currency units other than that or those in which the debt securities are denominated, the manner in which the exchange rate with respect to these payments will be determined;

•the manner in which the amounts of payment of principal of, premium, if any, or interest on the debt securities will be determined, if these amounts may be determined by reference to an index based on a currency or currencies or by reference to a commodity, commodity index, stock exchange index or financial index;

•any provisions relating to any security provided for the debt securities;

•any addition to, deletion of or change in the Events of Default described in this prospectus or in the indenture with respect to the debt securities and any change in the acceleration provisions described in this prospectus or in the indenture with respect to the debt securities;

•any addition to, deletion of or change in the covenants described in this prospectus or in the indenture with respect to the debt securities;

•any depositaries, interest rate calculation agents, exchange rate calculation agents or other agents with respect to the debt securities;

•the provisions, if any, relating to conversion or exchange of any debt securities of such series, including if applicable, the conversion or exchange price and period, provisions as to whether conversion or exchange will be mandatory, the events requiring an adjustment of the conversion or exchange price and provisions affecting conversion or exchange;

•any other terms of the debt securities, which may supplement, modify or delete any provision of the indenture as it applies to that series, including any terms that may be required under applicable law or regulations or advisable in connection with the marketing of the securities; and

•whether any of our direct or indirect subsidiaries will guarantee the debt securities of that series, including the terms of subordination, if any, of such guarantees. (Section 2.2)

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide

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you with information on the federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of the debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of and any premium and interest on any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company (the “Depositary”) or a nominee of the Depositary (we will refer to any debt security represented by a global debt security as a “book-entry debt security”), or a certificate issued in definitive registered form (we will refer to any debt security represented by a certificated security as a “certificated debt security”) as set forth in the applicable prospectus supplement. Except as set forth under the heading “Global Debt Securities and Book-Entry System” below, book-entry debt securities will not be issuable in certificated form.

Certificated Debt Securities. You may transfer or exchange certificated debt securities at any office we maintain for this purpose in accordance with the terms of the indenture. (Section 2.4) No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange. (Section 2.7)

You may effect the transfer of certificated debt securities and the right to receive the principal of, premium and interest on certificated debt securities only by surrendering the certificate representing those certificated debt securities and either reissuance by us or the trustee of the certificate to the new holder or the issuance by us or the trustee of a new certificate to the new holder.

Global Debt Securities and Book-Entry System. Each global debt security representing book-entry debt securities will be deposited with, or on behalf of, the Depositary, and registered in the name of the Depositary or a nominee of the Depositary. Please see “Global Securities.”

Covenants

We will set forth in the applicable prospectus supplement any restrictive covenants applicable to any issue of debt securities. (Article IV)

No Protection in the Event of a Change of Control

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions which may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control), which could adversely affect holders of debt securities.

Consolidation, Merger and Sale of Assets

We may not consolidate with or merge with or into, or convey, transfer or lease all or substantially all of our properties and assets to any person (a “successor person”) unless:

•we are the surviving entity or the successor person (if other than GRAIL) is a corporation, partnership, trust or other entity organized and validly existing under the laws of any U.S. domestic jurisdiction and expressly assumes our obligations on the debt securities and under the indenture; and

•immediately after giving effect to the transaction, no default or Event of Default (as defined below), shall have occurred and be continuing.

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Notwithstanding the above, any of our subsidiaries may consolidate with, merge into or transfer all or part of its properties to us. (Section 5.1)

Events of Default

“Event of Default” means with respect to any series of debt securities, any of the following:

•default in the payment of any interest upon any debt security of that series when it becomes due and payable, and continuance of such default for a period of 30 days (unless the entire amount of the payment is deposited by us with the trustee or with a paying agent prior to the expiration of the 30-day period);

•default in the payment of principal of any security of that series at its maturity;

•default in the performance or breach of any other covenant or warranty by us in the indenture (other than a covenant or warranty that has been included in the indenture solely for the benefit of a series of debt securities other than that series), which default continues uncured for a period of 60 days after we receive written notice from the trustee or GRAIL and the trustee receive written notice from the holders of not less than 25% in principal amount of the outstanding debt securities of that series as provided in the indenture;

•certain voluntary or involuntary events of bankruptcy, insolvency or reorganization of GRAIL;

•any other Event of Default provided with respect to debt securities of that series that is described in the applicable prospectus supplement. (Section 6.1)

No Event of Default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an Event of Default with respect to any other series of debt securities. (Section 6.1) The occurrence of certain Events of Default or an acceleration under the indenture may constitute an event of default under certain indebtedness of ours or our subsidiaries outstanding from time to time.

We will provide the trustee written notice of any default or Event of Default within 30 days of becoming aware of the occurrence of such default or Event of Default, which notice will describe in reasonable detail the status of such default or Event of Default and what action we are taking or propose to take in respect thereof. (Section 6.1)

If an Event of Default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than 25% in principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal of (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) and accrued and unpaid interest, if any, on all debt securities of that series. In the case of an Event of Default resulting from certain events of bankruptcy, insolvency or reorganization, the principal (or such specified amount) of and accrued and unpaid interest, if any, on all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, but before a judgment or decree for payment of the money due has been obtained by the trustee, the holders of a majority in principal amount of the outstanding debt securities of that series may rescind and annul the acceleration if all Events of Default, other than the non-payment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the indenture. (Section 6.2) We refer you to the prospectus supplement relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of such discount securities upon the occurrence of an Event of Default.

The indenture provides that the trustee may refuse to perform any duty or exercise any of its rights or powers under the indenture unless the trustee receives indemnity satisfactory to it against any cost, liability or expense which might be incurred by it in performing such duty or exercising such right or power. (Section 7.1(e)) Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available

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to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series. (Section 6.12)

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

•that holder has previously given to the trustee written notice of a continuing Event of Default with respect to debt securities of that series; and

•the holders of not less than 25% in principal amount of the outstanding debt securities of that series have made written request, and offered indemnity or security satisfactory to the trustee, to the trustee to institute the proceeding as trustee, and the trustee has not received from the holders of not less than a majority in principal amount of the outstanding debt securities of that series a direction inconsistent with that request and has failed to institute the proceeding within 60 days. (Section 6.7)

Notwithstanding any other provision in the indenture, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, premium and any interest on that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of payment. (Section 6.8)

The indenture requires us, within 120 days after the end of our fiscal year, to furnish to the trustee a statement as to compliance with the indenture. (Section 4.3) If a default or Event of Default occurs and is continuing with respect to the securities of any series and if it is known to a responsible officer of the trustee, the trustee shall mail to each Securityholder of the securities of that series notice of a default or Event of Default within 90 days after it occurs or, if later, after a responsible officer of the trustee has knowledge of such default or Event of Default. The indenture provides that the trustee may withhold notice to the holders of debt securities of any series of any default or Event of Default (except in payment on any debt securities of that series) with respect to debt securities of that series if the trustee determines in good faith that withholding notice is in the interest of the holders of those debt securities. (Section 7.5)

Modification and Waiver

We and the trustee may modify, amend or supplement the indenture or the debt securities of any series without the consent of any holder of any debt security:

•to cure any ambiguity, defect or inconsistency;

•to comply with covenants in the indenture described above under the heading “Consolidation, Merger and Sale of Assets”;

•to provide for uncertificated securities in addition to or in place of certificated securities;

•to add guarantees with respect to debt securities of any series or secure debt securities of any series;

•to surrender any of our rights or powers under the indenture;

•to add covenants or events of default for the benefit of the holders of debt securities of any series;

•to comply with the applicable procedures of the applicable depositary;

•to make any change that does not adversely affect the rights of any holder of debt securities;

•to provide for the issuance of and establish the form and terms and conditions of debt securities of any series as permitted by the indenture;

•to effect the appointment of a successor trustee with respect to the debt securities of any series and to add to or change any of the provisions of the indenture to provide for or facilitate administration by more than one trustee; or

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•to comply with requirements of the SEC in order to effect or maintain the qualification of the indenture under the Trust Indenture Act of 1939, as amended. (Section 9.1)

We may also modify and amend the indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We may not make any modification or amendment without the consent of the holders of each affected debt security then outstanding if that amendment will:

•reduce the amount of debt securities whose holders must consent to an amendment, supplement or waiver;

•reduce the rate of or extend the time for payment of interest (including default interest) on any debt security;

•reduce the principal of or premium on or change the fixed maturity of any debt security or reduce the amount of, or postpone the date fixed for, the payment of any sinking fund or analogous obligation with respect to any series of debt securities;

•reduce the principal amount of discount securities payable upon acceleration of maturity;

•waive a default in the payment of the principal of, premium or interest on any debt security (except a rescission of acceleration of the debt securities of any series by the holders of at least a majority in aggregate principal amount of the then outstanding debt securities of that series and a waiver of the payment default that resulted from such acceleration);

•make the principal of or premium or interest on any debt security payable in currency other than that stated in the debt security;

•make any change to certain provisions of the indenture relating to, among other things, the right of holders of debt securities to receive payment of the principal of, premium and interest on those debt securities and to institute suit for the enforcement of any such payment and to waivers or amendments; or

•waive a redemption payment with respect to any debt security. (Section 9.3)

Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive our compliance with provisions of the indenture. (Section 9.2) The holders of a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all the debt securities of such series waive any past default under the indenture with respect to that series and its consequences, except a default in the payment of the principal of, premium or any interest on any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration. (Section 6.13)

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, we may be discharged from any and all obligations in respect of the debt securities of any series (subject to certain exceptions). We will be so discharged upon the irrevocable deposit with the trustee, in trust, of money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. Dollars, government obligations of the government that issued or caused to be issued such currency, that, through the payment of interest and principal in accordance with their terms, will provide money or U.S. government obligations in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants or investment bank to pay and discharge each installment of principal, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities.

This discharge may occur only if, among other things, we have delivered to the trustee an opinion of counsel stating that we have received from, or there has been published by, the United States Internal Revenue Service a

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ruling or, since the date of execution of the indenture, there has been a change in the applicable United States federal income tax law, in either case to the effect that, and based thereon such opinion shall confirm that, the beneficial owners of the debt securities of that series will not recognize income, gain or loss for United States federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to United States federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred. (Section 8.3)

Defeasance of Certain Covenants. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, upon compliance with certain conditions:

•we may omit to comply with the covenant described under the heading “Consolidation, Merger and Sale of Assets” and certain other covenants set forth in the indenture, as well as any additional covenants which may be set forth in the applicable prospectus supplement; and

•any omission to comply with those covenants will not constitute a default or an Event of Default with respect to the debt securities of that series (covenant defeasance).

The conditions include:

•depositing with the trustee money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. dollars, government obligations of the government that issued or caused to be issued such currency, that, through the payment of interest and principal in accordance with their terms, will provide money in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants or investment bank to pay and discharge each installment of principal of, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities; and

•delivering to the trustee an opinion of counsel to the effect that the holders of the debt securities of that series will not recognize income, gain or loss for United States federal income tax purposes as a result of the deposit and related covenant defeasance and will be subject to United States federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit and related covenant defeasance had not occurred. (Section 8.4)

No Personal Liability of Directors, Officers, Employees or Securityholders

None of our past, present or future directors, officers, employees or securityholders, as such, will have any liability for any of our obligations under the debt securities or the indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a debt security, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the debt securities. However, this waiver and release may not be effective to waive liabilities under U.S. federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Governing Law

The indenture and the debt securities, including any claim or controversy arising out of or relating to the indenture or the securities, will be governed by the laws of the State of New York.

The indenture will provide that we, the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to the indenture, the debt securities or the transactions contemplated thereby.

The indenture will provide that any legal suit, action or proceeding arising out of or based upon the indenture or the transactions contemplated thereby may be instituted in the federal courts of the United States of America located in the City of New York or the courts of the State of New York in each case located in the City of New York, and we, the trustee and the holder of the debt securities (by their acceptance of the debt securities) irrevocably submit to

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the non-exclusive jurisdiction of such courts in any such suit, action or proceeding. The indenture will further provide that service of any process, summons, notice or document by mail (to the extent allowed under any applicable statute or rule of court) to such party’s address set forth in the indenture will be effective service of process for any suit, action or other proceeding brought in any such court. The indenture will further provide that we, the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the courts specified above and irrevocably and unconditionally waive and agree not to plead or claim any such suit, action or other proceeding has been brought in an inconvenient forum. (Section 10.10)

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DESCRIPTION OF OTHER SECURITIES

We will set forth in the applicable prospectus supplement a description of any warrants, purchase contracts, units or subscription rights issued by us that may be offered and sold pursuant to this prospectus.

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GLOBAL SECURITIES

Book-Entry; Delivery and Form

Unless we indicate differently in any applicable prospectus supplement or free writing prospectus, the securities initially will be issued in book-entry form and represented by one or more global notes or global securities (collectively, “global securities”). The global securities will be deposited with, or on behalf of, The Depository Trust Company, New York, New York, as depositary (“DTC”), and registered in the name of Cede & Co., the nominee of DTC. Unless and until it is exchanged for individual certificates evidencing securities under the limited circumstances described below, a global security may not be transferred except as a whole by the depositary to its nominee or by the nominee to the depositary, or by the depositary or its nominee to a successor depositary or to a nominee of the successor depositary.

DTC has advised us that it is:

•a limited-purpose trust company organized under the New York Banking Law;

•a “banking organization” within the meaning of the New York Banking Law;

•a member of the Federal Reserve System;

•a “clearing corporation” within the meaning of the New York Uniform Commercial Code; and

•a “clearing agency” registered pursuant to the provisions of Section 17A of the Exchange Act.

DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among its participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in participants’ accounts, thereby eliminating the need for physical movement of securities certificates. “Direct participants” in DTC include securities brokers and dealers, including underwriters, banks, trust companies, clearing corporations and other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation (“DTCC”). DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others, which we sometimes refer to as indirect participants, that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit for the securities on DTC’s records. The ownership interest of the actual purchaser of a security, which we sometimes refer to as a beneficial owner, is in turn recorded on the direct and indirect participants’ records. Beneficial owners of securities will not receive written confirmation from DTC of their purchases. However, beneficial owners are expected to receive written confirmations providing details of their transactions, as well as periodic statements of their holdings, from the direct or indirect participants through which they purchased securities. Transfers of ownership interests in global securities are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the global securities, except under the limited circumstances described below.

To facilitate subsequent transfers, all global securities deposited by direct participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of securities with DTC and their registration in the name of Cede & Co. or such other nominee will not change the beneficial ownership of the securities. DTC has no knowledge of the actual beneficial owners of the securities. DTC’s records reflect only the identity of the direct participants to whose accounts the securities are credited, which may or may not be the beneficial owners. The participants are responsible for keeping account of their holdings on behalf of their customers.

So long as the securities are in book-entry form, you will receive payments and may transfer securities only through the facilities of the depositary and its direct and indirect participants. We will maintain an office or agency in the location specified in the prospectus supplement for the applicable securities, where notices and demands in

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respect of the securities and the indenture may be delivered to us and where certificated securities may be surrendered for payment, registration of transfer or exchange.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants and by direct participants and indirect participants to beneficial owners will be governed by arrangements among them, subject to any legal requirements in effect from time to time.

Redemption notices will be sent to DTC. If less than all of the securities of a particular series are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each direct participant in the securities of such series to be redeemed.

Neither DTC nor Cede & Co. (or such other DTC nominee) will consent or vote with respect to the securities. Under its usual procedures, DTC will mail an omnibus proxy to us as soon as possible after the record date. The omnibus proxy assigns the consenting or voting rights of Cede & Co. to those direct participants to whose accounts the securities of such series are credited on the record date, identified in a listing attached to the omnibus proxy.

So long as securities are in book-entry form, we will make payments on those securities to the depositary or its nominee, as the registered owner of such securities, by wire transfer of immediately available funds. If securities are issued in definitive certificated form under the limited circumstances described below and unless if otherwise provided in the description of the applicable securities herein or in the applicable prospectus supplement, we will have the option of making payments by check mailed to the addresses of the persons entitled to payment or by wire transfer to bank accounts in the United States designated in writing to the applicable trustee or other designated party at least 15 days before the applicable payment date by the persons entitled to payment, unless a shorter period is satisfactory to the applicable trustee or other designated party.

Redemption proceeds, distributions and dividend payments on the securities will be made to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit direct participants’ accounts upon DTC’s receipt of funds and corresponding detail information from us on the payment date in accordance with their respective holdings shown on DTC records. Payments by participants to beneficial owners will be governed by standing instructions and customary practices, as is the case with securities held for the account of customers in bearer form or registered in “street name.” Those payments will be the responsibility of participants and not of DTC or us, subject to any statutory or regulatory requirements in effect from time to time. Payment of redemption proceeds, distributions and dividend payments to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC, is our responsibility, disbursement of payments to direct participants is the responsibility of DTC, and disbursement of payments to the beneficial owners is the responsibility of direct and indirect participants.

Except under the limited circumstances described below, purchasers of securities will not be entitled to have securities registered in their names and will not receive physical delivery of securities. Accordingly, each beneficial owner must rely on the procedures of DTC and its participants to exercise any rights under the securities and the indenture.

The laws of some jurisdictions may require that some purchasers of securities take physical delivery of securities in definitive form. Those laws may impair the ability to transfer or pledge beneficial interests in securities.

DTC may discontinue providing its services as securities depositary with respect to the securities at any time by giving reasonable notice to us. Under such circumstances, in the event that a successor depositary is not obtained, securities certificates are required to be printed and delivered.

As noted above, beneficial owners of a particular series of securities generally will not receive certificates representing their ownership interests in those securities. However, if:

•DTC notifies us that it is unwilling or unable to continue as a depositary for the global security or securities representing such series of securities or if DTC ceases to be a clearing agency registered under the Exchange Act at a time when it is required to be registered and a successor depositary is not appointed

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within 90 days of the notification to us or of our becoming aware of DTC’s ceasing to be so registered, as the case may be;

•we determine, in our sole discretion, not to have such securities represented by one or more global securities; or

•an Event of Default has occurred and is continuing with respect to such series of securities,

we will prepare and deliver certificates for such securities in exchange for beneficial interests in the global securities. Any beneficial interest in a global security that is exchangeable under the circumstances described in the preceding sentence will be exchangeable for securities in definitive certificated form registered in the names that the depositary directs. It is expected that these directions will be based upon directions received by the depositary from its participants with respect to ownership of beneficial interests in the global securities.

Euroclear and Clearstream

If so provided in the applicable prospectus supplement, you may hold interests in a global security through Clearstream Banking S.A. (“Clearstream”) or Euroclear Bank SA/NV, as operator of the Euroclear System (“Euroclear”), either directly if you are a participant in Clearstream or Euroclear or indirectly through organizations which are participants in Clearstream or Euroclear. Clearstream and Euroclear will hold interests on behalf of their respective participants through customers’ securities accounts in the names of Clearstream and Euroclear, respectively, on the books of their respective U.S. depositaries, which in turn will hold such interests in customers’ securities accounts in such depositaries’ names on DTC’s books.

Clearstream and Euroclear are securities clearance systems in Europe. Clearstream and Euroclear hold securities for their respective participating organizations and facilitate the clearance and settlement of securities transactions between those participants through electronic book-entry changes in their accounts, thereby eliminating the need for physical movement of certificates.

Payments, deliveries, transfers, exchanges, notices and other matters relating to beneficial interests in global securities owned through Euroclear or Clearstream must comply with the rules and procedures of those systems. Transactions between participants in Euroclear or Clearstream, on one hand, and other participants in DTC, on the other hand, are also subject to DTC’s rules and procedures.

Investors will be able to make and receive through Euroclear and Clearstream payments, deliveries, transfers and other transactions involving any beneficial interests in global securities held through those systems only on days when those systems are open for business. Those systems may not be open for business on days when banks, brokers and other institutions are open for business in the United States.

Cross-market transfers between participants in DTC, on the one hand, and participants in Euroclear or Clearstream, on the other hand, will be effected through DTC in accordance with the DTC’s rules on behalf of Euroclear or Clearstream, as the case may be, by their respective U.S. depositaries; however, such cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in such system in accordance with the rules and procedures and within the established deadlines (European time) of such system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving interests in the global securities through DTC, and making or receiving payment in accordance with normal procedures for same-day fund settlement. Participants in Euroclear or Clearstream may not deliver instructions directly to their respective U.S. depositaries.

Due to time zone differences, the securities accounts of a participant in Euroclear or Clearstream purchasing an interest in a global security from a direct participant in DTC will be credited, and any such crediting will be reported to the relevant participant in Euroclear or Clearstream, during the securities settlement processing day (which must be a business day for Euroclear or Clearstream) immediately following the settlement date of DTC. Cash received in Euroclear or Clearstream as a result of sales of interests in a global security by or through a participant in Euroclear or Clearstream to a direct participant in DTC will be received with value on the settlement date of DTC but will be

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available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC’s settlement date.

Other

The information in this section of this prospectus concerning DTC, Clearstream, Euroclear and their respective book-entry systems has been obtained from sources that we believe to be reliable, but we do not take responsibility for this information. This information has been provided solely as a matter of convenience. The rules and procedures of DTC, Clearstream and Euroclear are solely within the control of those organizations and could change at any time. Neither we nor the trustee nor any agent of ours or of the trustee has any control over those entities and none of us takes any responsibility for their activities. You are urged to contact DTC, Clearstream and Euroclear or their respective participants directly to discuss those matters. In addition, although we expect that DTC, Clearstream and Euroclear will perform the foregoing procedures, none of them is under any obligation to perform or continue to perform such procedures and such procedures may be discontinued at any time. Neither we nor any agent of ours will have any responsibility for the performance or nonperformance by DTC, Clearstream and Euroclear or their respective participants of these or any other rules or procedures governing their respective operations.

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SELLING SECURITYHOLDERS

Information about selling securityholders, where applicable, will be set forth in a prospectus supplement, in a post-effective amendment or in filings we make with the SEC under the Exchange Act that are incorporated by reference.

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PLAN OF DISTRIBUTION

We or any of the selling securityholders may sell the offered securities from time to time:

•through underwriters or dealers;

•through agents;

•directly to one or more purchasers; or

•through a combination of any of these methods of sale.

We will identify the specific plan of distribution, including any underwriters, dealers, agents or direct purchasers and their compensation in the applicable prospectus supplement.

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LEGAL MATTERS

Latham & Watkins LLP will pass upon certain legal matters relating to the issuance and sale of the securities offered hereby on behalf of GRAIL, Inc. Additional legal matters may be passed upon for us, the selling securityholders or any underwriters, dealers or agents by counsel that we will name in the applicable prospectus supplement.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2024, as set forth in their report, which is incorporated by reference in this prospectus and elsewhere in the registration statement. Our consolidated financial statements are incorporated by reference in reliance on Ernst & Young LLP’s report, given on their authority as experts in accounting and auditing.

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GRAIL, Inc.

3,925,767 Shares

Common Stock

Offered by the Selling Stockholders

FAQ

What is GRAIL (GRAL) registering in this 424(b)(7) filing?

A proposed resale of up to 3,925,767 shares of common stock by selling stockholders, including 1,927,194 common shares and 1,998,573 shares underlying pre-funded warrants.

Will GRAIL receive proceeds from the selling stockholders’ sales?

No. GRAIL will not receive any proceeds from holder sales. It would receive the nominal $0.001 per-share exercise price if pre-funded warrants are exercised for cash.

What are examples of per‑holder amounts offered for resale?

Including Deep Track Biotechnology Master Fund, Ltd. 927,909 and Farallon affiliates 571,021. These are examples only and do not represent a total.

How many shares of GRAL were outstanding as of the latest date provided?

Shares outstanding were 38,981,593 as of October 31, 2025.

What is the status and price context for GRAL shares?

GRAL is listed on the Nasdaq Global Select Market. The last reported sale price was $84.77 on November 12, 2025.

What sale methods may selling stockholders use?

Methods include brokerage transactions, block trades, privately negotiated transactions, and short sales after the registration statement is declared effective.

Why is GRAIL registering these shares now?

To satisfy obligations under the 2025 Registration Rights Agreement related to a private placement of common stock and pre-funded warrants.