PRIMECAP Management (GRAL) discloses 21.8M-share, 5.08% stake in GRAIL

Rhea-AI Filing Summary

PRIMECAP Management Co. reports a significant ownership position in GRAIL, Inc. common stock. As of the reported date, PRIMECAP beneficially owned 21,801,016 shares, representing 5.08% of GRAIL’s outstanding common shares.

Within this stake, PRIMECAP has sole power to vote 2,174,440 shares and sole power to dispose of 2,180,106 shares, with no shared voting or dispositive power disclosed. This filing is identified as Amendment No. 3 to a previous ownership report.

Key Figures

Beneficial ownership: 21,801,016 shares Percent of class: 5.08% Sole voting power: 2,174,440 shares +3 more

6 metrics

Beneficial ownership 21,801,016 shares Amount of GRAIL, Inc. common stock beneficially owned by PRIMECAP

Percent of class 5.08% Percentage of GRAIL, Inc. common stock class beneficially owned

Sole voting power 2,174,440 shares Shares of GRAIL common stock over which PRIMECAP has sole power to vote

Sole dispositive power 2,180,106 shares Shares of GRAIL common stock over which PRIMECAP has sole power to dispose

Shared voting power 0 shares Shares with shared power to vote reported by PRIMECAP

Shared dispositive power 0 shares Shares with shared power to dispose reported by PRIMECAP

Key Terms

beneficially owned, sole power to vote, sole power to dispose, percent of class

4 terms

beneficially owned financial

"Amount beneficially owned: 21,801,016 (b) | Percent of class: 5.08 %"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole power to vote financial

"Number of shares as to which the person has | (i) Sole power to vote"

sole power to dispose financial

"(iii) Sole power to dispose or to direct the disposition of"

percent of class financial

"(b) | Percent of class: 5.08 %"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/06/2026 - 05:03 PM Accepted by SEC EDGAR 08/06/2026 - 05:01 PM Learn about SEC filing dates

FAQ

What ownership stake in GRAIL, Inc. (GRAL) does PRIMECAP report?

PRIMECAP Management Co. reports beneficial ownership of 21,801,016 shares of GRAIL, Inc. common stock, representing 5.08% of the class. This reflects its reported holdings as of the stated date.

How many GRAIL (GRAL) shares can PRIMECAP vote and dispose of?

PRIMECAP has sole voting power over 2,174,440 shares and sole dispositive power over 2,180,106 shares of GRAIL common stock. It reports no shared voting or dispositive power.

What is the significance of Amendment No. 3 for GRAIL (GRAL)?

Amendment No. 3 updates PRIMECAP’s Schedule 13G disclosure on its GRAIL holdings. It restates its 21,801,016 shares beneficially owned, equal to 5.08% of GRAIL’s common stock, as of the reported date.

Who is the institutional holder reporting this GRAIL (GRAL) position?

The reporting person is PRIMECAP Management Co., with its principal business office at 177 East Colorado Blvd., 11th Floor, Pasadena, California 91105. It is identified as a United States entity.

What class of GRAIL (GRAL) securities is covered in this ownership report?

The filing covers common stock (COM) of GRAIL, Inc. PRIMECAP reports 21,801,016 common shares beneficially owned, representing 5.08% of this class of securities.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)

GRAIL, Inc.

(Name of Issuer)

COM

(Title of Class of Securities)

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP No.

1

Names of Reporting Persons

PRIMECAP MANAGEMENT CO/CA/

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,174,440.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,180,106.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

21,801,016.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.08 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: GRAIL, Inc.
(b)	Address of issuer's principal executive offices: 1525 O'BRIEN DRIVE, MENLO PARK, CALIFORNIA 94025
Item 2.
(a)	Name of person filing: PRIMECAP MANAGEMENT CO/CA/
(b)	Address or principal business office or, if none, residence: 177 EAST COLORADO BLVD. 11TH FLOOR PASADENA, California 91105
(c)	Citizenship: PRIMECAP MANAGEMENT CO/CA/ - UNITED STATES
(d)	Title of class of securities: COM
(e)	CUSIP No.:
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 21,801,016
(b)	Percent of class: 5.08 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: PRIMECAP MANAGEMENT CO/CA/ - 2,174,440
	(ii) Shared power to vote or to direct the vote: PRIMECAP MANAGEMENT CO/CA/ - 0
	(iii) Sole power to dispose or to direct the disposition of: PRIMECAP MANAGEMENT CO/CA/ - 2,180,106
	(iv) Shared power to dispose or to direct the disposition of: PRIMECAP MANAGEMENT CO/CA/ - 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

PRIMECAP MANAGEMENT CO/CA/

Signature:	JENNIFER
Name/Title:	OTTOSEN
Date:	08/06/2026