Gilead boosts Assembly Biosciences (NASDAQ: ASMB) ownership to 25.1% of shares

Rhea-AI Filing Summary

Gilead Sciences filed an amended ownership report showing a larger stake in Assembly Biosciences. Gilead now beneficially owns 4,977,089 shares of Assembly common stock, representing 25.1% of the outstanding shares based on 19,816,995 shares outstanding after the company’s most recent public offering.

On May 26, 2026, Gilead bought 471,698 Assembly shares in an underwritten public offering for total consideration of approximately $12,499,997, funded from its cash resources. Gilead also holds warrants covering 2,475,420 additional shares, but a 19.99% Beneficial Ownership Limitation means those underlying shares are not currently counted as beneficially owned.

Insights

Equity ownership and biotech partnerships analyst

Gilead increases its equity stake in Assembly Biosciences to a significant minority position.

Gilead Sciences now reports beneficial ownership of 4,977,089 shares of Assembly Biosciences common stock, equal to 25.1% of shares outstanding after Assembly’s latest public offering of 19,816,995 shares. This reflects both prior holdings and new shares bought in that offering.

Gilead purchased 471,698 shares in the underwritten offering for about $12,499,997, using its available cash. It also holds warrants over 2,475,420 additional shares, but a 19.99% Beneficial Ownership Limitation prevents exercises that would push reported ownership above that threshold, so those underlying shares are excluded from current beneficial ownership.

This filing updates prior ownership disclosures and confirms Gilead’s role as a large minority holder rather than a controlling shareholder. Future company reports may clarify how this stake and the outstanding warrants interact with Assembly’s governance, collaborations, or capital structure over time.

Key Figures

Beneficially owned shares: 4,977,089 shares Ownership percentage: 25.1% Shares outstanding baseline: 19,816,995 shares +6 more

9 metrics

Beneficially owned shares 4,977,089 shares Gilead’s reported Assembly Biosciences common stock holdings

Ownership percentage 25.1% Portion of Assembly Biosciences common stock held by Gilead

Shares outstanding baseline 19,816,995 shares Assembly shares outstanding after most recent public offering

Prospectus supplement shares 19,250,955 shares Shares issued and outstanding after offering per prospectus supplement

Underwriters’ option shares 566,040 shares Additional Assembly shares from underwriters’ option exercise

New shares purchased 471,698 shares Assembly shares bought by Gilead in May 2026 offering

Purchase consideration $12,499,997 Total consideration paid by Gilead for 471,698 shares

Warrant underlying shares 2,475,420 shares Aggregate Assembly shares underlying Gilead’s warrants

Beneficial Ownership Limitation 19.99% Maximum ownership allowed under Gilead’s Assembly warrants

Key Terms

underwritten public offering, beneficially owned, Beneficial Ownership Limitation, warrant, +2 more

6 terms

underwritten public offering financial

"On May 26, 2026, Gilead purchased 471,698 shares of Common Stock from the Issuer in an underwritten public offering."

An underwritten public offering is when a company sells new shares of its stock to the public with the help of a financial firm, called an underwriter. The underwriter agrees to buy all the shares upfront, reducing the company's risk, and then sells them to investors. This process helps companies raise money quickly and confidently from a wide range of buyers.

beneficially owned financial

"Number of shares beneficially owned: Gilead Sciences, Inc. - 4,977,089 Shares"

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.

Beneficial Ownership Limitation financial

"The Beneficial Ownership Limitation with respect to each Warrant is subject to adjustment upon 61 days' notice..."

A beneficial ownership limitation is a rule that caps the percentage of a company’s shares an investor can be treated as owning or controlling for voting, regulatory or tax purposes. It matters to investors because it can restrict how many shares a person or group can buy or vote, affect takeover chances, and influence share liquidity and value — like a speed limit that prevents any single driver from taking over the whole road.

warrant financial

"The Reporting Person beneficially owns a warrant to purchase 179,500 shares of Common Stock (the "2024 Warrant")..."

A warrant is a time-limited financial contract that gives its holder the right to buy a company's shares at a set price before a specified date, like a coupon that lets you purchase stock at a fixed discount for a limited time. It matters to investors because warrants offer leveraged exposure to a stock’s upside and can dilute existing shareholders if exercised, so they affect potential gains and the company’s outstanding share count.

Series A Warrant financial

"the Series A Warrant, and the Series B Warrant (collectively, the "Warrants")."

A Series A warrant is a contract issued alongside a company’s early funding round that gives the holder the right to buy a set number of shares later at a fixed price. Think of it like a coupon that lets an investor purchase stock at today’s agreed price even if the company’s value rises; it can boost potential upside for the warrant holder and create dilution for existing shareholders, so investors watch them when assessing ownership and future share value.

Schedule 13D regulatory

"This Amendment No. 4 ("Amendment No. 4") amends and supplements the filed by the Reporting Person..."

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)

ASSEMBLY BIOSCIENCES, INC.

(Name of Issuer)

Common Stock, par value $0.001

(Title of Class of Securities)

045396108

(CUSIP Number)

Gilead Sciences, Inc.
333 Lakeside Drive,
Foster City, CA, 94404
650-574-3000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

05/22/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 045396108

1

Name of reporting person

GILEAD SCIENCES, INC.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 4,977,089.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 4,977,089.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

4,977,089.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

25.1 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

Comment relating to row 13: Based upon 19,816,995 shares of Common Stock of the Issuer issued and outstanding immediately following the closing of the Issuer's most recent public offering, including 19,250,955 shares as disclosed in the prospectus supplement (the "Prospectus Supplement") and an additional 566,040 shares issued pursuant to the underwriters' option to purchase additional shares as reported in the Current Report on Form 8-K (the "Form 8-K"), each filed with the Securities and Exchange Commission (the "SEC") on May 26, 2026.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.001
(b)	Name of Issuer: ASSEMBLY BIOSCIENCES, INC.
(c)	Address of Issuer's Principal Executive Offices: Two Tower Place, 7th Floor, South San Francisco, CALIFORNIA , 94080.
Item 1 Comment: This Amendment No. 4 ("Amendment No. 4") amends and supplements the Schedule 13D filed by the Reporting Person with the SEC on October 25, 2023, as amended by Amendment No. 1 filed with the SEC on June 20, 2024, Amendment No. 2 filed with the SEC on December 23, 2024 and Amendment No. 3 filed with the SEC on August 12, 2025 (as amended by Amendment No. 4, the "Schedule 13D"), which relates to the Common Stock of the Issuer. Unless otherwise indicated, all capitalized terms used herein shall have the meanings set forth in the Schedule 13D and, unless amended hereby, all information previously disclosed remains unchanged.
Item 2.	Identity and Background
(c)	Item 2(c) is amended and restated to read as follows: The principal business of the Reporting Person is to develop and commercialize innovative medicines in areas of unmet medical need and engage in any other activity or business lawfully carried on by a corporation organized under the laws of the State of Delaware. The directors and executive officers of the Reporting Person are set forth on Exhibit 99.1 filed herewith. Exhibit 99.1 sets forth the following information with respect to each such person: (i) name; (ii) business address; (iii) position with the Reporting Person and present principal occupation or employment and, for persons not employed by the Reporting Person, the name, principal business and address of any corporation or other organization in which such employment is conducted; and (iv) citizenship.
(f)	Item 2(f) is amended and restated to read as follows: The jurisdiction of organization of the Reporting Person is set forth in subsection (a) above. The citizenship of each of the individuals referred to in Exhibit 99.1 is set forth on Exhibit 99.1.
Item 3.	Source and Amount of Funds or Other Consideration
	Item 3 is amended to add the following paragraph immediately following the last paragraph: On May 26, 2026, Gilead purchased 471,698 shares of Common Stock from the Issuer in an underwritten public offering. The total consideration for such purchase was approximately $12,499,997 million and such consideration was obtained from the available cash resources of Gilead.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a) of the Schedule 13D is hereby amended and restated to read as follows: Number of shares beneficially owned: Gilead Sciences, Inc. - 4,977,089 Shares Percent of class: Gilead Sciences, Inc. - 25.1% The percent ownership was calculated based on 19,250,955 shares of Common Stock of the Issuer issued and outstanding immediately following the closing of the Issuer's most recent public offering, as disclosed in the Prospectus Supplement. based on 19,816,995 shares of Common Stock of the Issuer issued and outstanding immediately following the closing of the Issuer's most recent public offering, including 19,250,955 shares as disclosed in the Prospectus Supplement and an additional 566,040 shares issued pursuant to the underwriters' option to purchase additional shares as reported in the Form 8-K.
(b)	Item 5(b) of the Schedule 13D is hereby amended and restated to read as follows: (i) Sole power to vote or to direct the vote: Gilead Sciences, Inc. - 4,977,089 shares (ii) Shared power to vote or to direct the vote: Gilead Sciences, Inc. - 0 shares (iii) Sole power to dispose or to direct the disposition of: Gilead Sciences, Inc. - 4,977,089 shares (iv) Shared power to dispose or to direct the disposition of: Gilead Sciences, Inc. - 0 shares To the best knowledge of the Reporting Person, none of the individuals listed on Exhibit 99.1 beneficially owns any of the Issuer's Common Stock. The Reporting Person beneficially owns a warrant to purchase 179,500 shares of Common Stock (the "2024 Warrant") that was acquired from the Issuer on June 17, 2024, the Series A Warrant, and the Series B Warrant (collectively, the "Warrants"). Each of the Warrants is subject to a limitation pursuant to which the Reporting Persons may not exercise such Warrant if such exercise would cause the Reporting Person to beneficially own Common Stock in an amount exceeding the "Beneficial Ownership Limitation" (as defined in such Warrant) then in effect. The Beneficial Ownership Limitation with respect to each Warrant is subject to adjustment upon 61 days' notice by the holder of such Warrant to the Issuer and, as of the date of this Amendment No. 3, was 19.99% of the number of shares of Common Stock outstanding. As a result, none of the aggregate of 2,475,420 shares of Common Stock underlying the Warrants are deemed to be beneficially owned by the Reporting Persons.
(c)	Item 5(c) of the Schedule 13D is hereby amended and restated to read as follows: Except as reported in this Amendment No. 4, neither the Reporting Person nor, to the best knowledge of the Reporting Person, any of the individuals listed on Exhibit 99.1 have effected any transactions in the Common Stock during the past sixty (60) days.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 99.1 - List of Executive Officers and Directors of Gilead Sciences, Inc.

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.

GILEAD SCIENCES, INC.

Signature:	/s/ Andrew D. Dickinson
Name/Title:	Andrew D. Dickinson, Chief Financial Officer
Date:	05/27/2026

FAQ

How many ASMB shares does Gilead Sciences now beneficially own?

Gilead Sciences beneficially owns 4,977,089 shares of Assembly Biosciences (ASMB) common stock. This represents 25.1% of Assembly’s outstanding shares, calculated against 19,816,995 shares outstanding immediately after Assembly’s most recent underwritten public offering and related underwriters’ option exercise.

What percentage of Assembly Biosciences (ASMB) does Gilead’s stake represent?

Gilead’s stake in Assembly Biosciences represents 25.1% of the company’s common stock. This percentage is based on 19,816,995 Assembly shares outstanding following its latest public offering, including 19,250,955 shares from the prospectus supplement and 566,040 shares from the underwriters’ option.

How many ASMB shares did Gilead purchase in the latest offering and for how much?

Gilead purchased 471,698 Assembly Biosciences shares in the underwritten public offering. The total consideration was approximately $12,499,997, funded from Gilead’s available cash resources, and this transaction contributed to its reported 25.1% beneficial ownership of Assembly’s common stock.

What is the total number of ASMB shares outstanding used in Gilead’s ownership calculation?

The ownership calculation uses 19,816,995 Assembly Biosciences shares outstanding immediately after its latest offering. This includes 19,250,955 shares disclosed in the prospectus supplement and 566,040 additional shares issued when underwriters exercised their option to purchase extra shares, as reported in a Form 8-K.

Does Gilead hold any warrants for additional ASMB shares?

Yes. Gilead holds warrants covering an aggregate 2,475,420 Assembly Biosciences shares, including a 2024 Warrant, a Series A Warrant, and a Series B Warrant. However, due to a 19.99% Beneficial Ownership Limitation, these underlying shares are not currently treated as beneficially owned.

What voting and dispositive power does Gilead have over its ASMB shares?

Gilead has sole voting power and sole dispositive power over 4,977,089 Assembly Biosciences shares. It reports no shared voting or shared dispositive power. This means Gilead alone decides how these shares are voted and whether or when they may be sold or otherwise transferred.