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NASDAQ: ASMB ASSEMBLY BIOSCIENCES, INC. 8-K

Assembly Bio raises $107.4M net in equity offering of 3.9M shares at $26.50

Filed May 26, 2026 · Period ending May 21, 2026 · ~1 min read

5 key changes 1 high relevance 3 sections

Key Changes

  • high

    Completed underwritten offering of 3,358,602 common shares at $26.50 per share plus 415,000 pre-funded warrants at $26.499, raising $107.4M net after fees. Underwriters exercised full overallotment option for 566,040 additional shares.

    Item 1.01 — Entry into a Material Definitive Agreement verify on EDGAR →
  • medium

    Offering included participation from Gilead Sciences (existing collaboration partner), Farallon Capital, Commodore Capital, Columbia Threadneedle, and other healthcare-focused institutional investors.

    Exhibit 99.1 view on EDGAR →
  • medium

    Net proceeds will fund clinical development of pipeline candidates targeting viral and liver diseases and general corporate purposes. No specific allocation or program milestones disclosed.

    Exhibit 99.1 view on EDGAR →
  • low

    Pre-funded warrants have $0.001 exercise price, are immediately exercisable with no expiration, making them economically equivalent to common stock. Include 4.99% ownership blockers adjustable to 9.99% or 19.99% with notice.

    Item 1.01 — Entry into a Material Definitive Agreement verify on EDGAR →
  • low

    Executive officers and directors agreed to standard 90-day lock-up preventing share sales without underwriter consent.

    Item 1.01 — Entry into a Material Definitive Agreement verify on EDGAR →

Summary

Assembly Biosciences completed a $107.4 million equity financing through an underwritten offering of approximately 3.9 million common shares at $26.50 per share, plus pre-funded warrants for 415,000 shares. The offering attracted participation from both new and existing institutional investors, notably including Gilead Sciences, which maintains an existing collaboration with the company.

The underwriters exercised their full overallotment option, indicating solid demand. The capital raise will fund clinical development of Assembly's pipeline candidates targeting viral and liver diseases, including programs in herpesvirus, hepatitis delta virus, cholestatic liver diseases, and hepatitis B virus.

The filing does not specify how proceeds will be allocated across programs or tie funding to specific clinical milestones. The pre-funded warrants are structured with a nominal $0.001 exercise price and no expiration, making them functionally equivalent to common stock for dilution purposes. The approximately 4.3 million share increase represents material dilution to existing shareholders, though the participation of sophisticated healthcare investors and a strategic partner suggests confidence in the company's clinical pipeline.

Section-by-Section Diff

Event · Item 1.01 — Entry into a Material Definitive Agreement

~900 words

Item 1.01 — Entry into a Material Definitive Agreement filed; see Key Changes for terms.

3 Added
Added Equity offering completion high

Added in current filing · verify on EDGAR →

On May 21, 2026, Assembly Biosciences, Inc. (the "Company") entered into an underwriting agreement (the "Underwriting Agreement") with Guggenheim Securities, LLC ("Guggenheim Securities") and UBS Securities LLC, as representatives of the several underwriters listed in Schedule A thereto (the "Underwriters"), in connection with the issuance and sale, in an underwritten, registered offering (the "Offering"), of: (1) 3,358,602 shares (the "Offering Shares") of the Company's common stock, par value $0.001 per share (the "Common Stock"), at an offering price of $26.50 per share; and (2) pre-funded warrants (the "Pre-Funded Warrants") to purchase up to an aggregate of 415,000 shares of Common Stock (the "Pre-Funded Warrant Shares"), at an offering price of $26.499 per Pre-Funded Warrant.

Assembly Biosciences completed an underwritten public offering of 3,358,602 common shares at $26.50 per share and pre-funded warrants to purchase 415,000 shares at $26.499 per warrant. The pre-funded warrants have a nominal exercise price of $0.001 and are immediately exercisable with no expiration date, making them economically equivalent to common stock.

Added Net proceeds high

Added in current filing · verify on EDGAR →

The Company received net proceeds of approximately $107.4 million from the Offering and the Option Exercise, after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company.

Assembly Biosciences raised approximately $107.4 million in net proceeds after underwriting fees and expenses. The filing does not disclose the intended use of these proceeds.

Show 1 minor / wording change
Added Insider lock-up agreements low

Added in current filing · verify on EDGAR →

Subject to certain exceptions, the Company’s executive officers and directors agreed not to sell or otherwise dispose of any of the shares of Common Stock held by them for a period beginning on the date of execution of the applicable lock-up agreements by each such executive officer and director and ending 90 days after the date of the final prospectus supplement filed with the U.S. Securities and Exchange Commission (the “SEC”) in connection with the Offering pursuant to Rule 424(b) under the Securities Act of 1933, as amended, without first obtaining the written consent of Guggenheim Securities.

Executive officers and directors agreed to a 90-day lock-up period preventing them from selling their existing shares without underwriter consent. This is a standard provision in underwritten offerings to prevent insider selling pressure immediately following the offering.

Event · Exhibit 99.1

Assembly Biosciences priced a $100M equity offering at $26.50/share to fund clinical development of pipeline candidates.

2 Added
Added Equity offering pricing high

Added in current filing · view on EDGAR →

Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral and liver diseases, today announced the pricing of an underwritten, registered offering (the offering) of an aggregate of 3,358,602 shares of common stock at an offering price per share of common stock of $26.50, and, to certain investors in lieu of common stock, pre-funded warrants to purchase up to 415,000 shares of common stock at an offering price per pre-funded warrant of $26.499, which represents the per share offering price of the common stock less the $0.001 exercise price per share for each pre-funded warrant. Gross proceeds from the offering, before deducting underwriting discounts and commissions and other offering expenses, are expected to be approximately $100 million.

Assembly Biosciences priced a registered equity offering of 3,358,602 common shares at $26.50 per share plus 415,000 pre-funded warrants at $26.499 each, for gross proceeds of approximately $100 million before fees. The offering includes a 30-day greenshoe option for underwriters to purchase up to 566,040 additional shares. The offering is expected to close on or about May 26, 2026.

Added Use of proceeds high

Added in current filing · view on EDGAR →

Assembly Bio plans to use the net proceeds from the offering to fund clinical development of pipeline candidates and for general corporate purposes.

The company intends to use net proceeds from the offering to fund clinical development of its pipeline candidates targeting viral and liver diseases, as well as for general corporate purposes. This capital raise will support ongoing development programs in herpesvirus, hepatitis delta virus, cholestatic liver diseases, and hepatitis B virus.

Event · Exhibit 99.2

3 Added
Added Equity offering closure high

Added in current filing · view on EDGAR →

Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral and liver diseases, today announced the closing of its previously announced underwritten registered offering of 3,924,624 shares of its common stock at an offering price per share of common stock of $26.50, which includes the exercise in full by the underwriters of their option to purchase 566,040 additional shares of common stock. In addition, and in lieu of common stock, Assembly Bio sold to a certain existing investor pre-funded warrants to purchase up to an aggregate of 415,000 shares of common stock at an offering price per pre-funded warrant of $26.499, which represents the per share offering price of the common stock less the $0.001 per share exercise price for each such pre-funded warrant. The aggregate gross proceeds to Assembly Bio from this offering were approximately $115.0 million before deducting underwriting discounts and commissions and other offering expenses payable by the company.

Assembly Bio completed an equity financing raising approximately $115 million gross proceeds through the sale of 3,924,624 common shares at $26.50 per share and pre-funded warrants for 415,000 shares at $26.499 per warrant. The underwriters exercised their full over-allotment option to purchase an additional 566,040 shares. This dilutive financing increases the share count by approximately 4.3 million shares (including warrant shares).

Added Use of proceeds medium

Added in current filing · view on EDGAR →

Assembly Bio intends to use the net proceeds from the sale of the common stock and pre-funded warrants to fund clinical development of pipeline candidates and for general corporate purposes.

The company plans to deploy the net proceeds toward clinical development of its pipeline candidates and general corporate purposes. This capital infusion should extend the company's cash runway and support ongoing clinical trials in viral and liver disease therapeutics.

Show 1 minor / wording change
Added Underwriter syndicate low

Added in current filing · view on EDGAR →

Guggenheim Securities and UBS Investment Bank acted as joint book-running managers for the offering. Mizuho is also acted as a book-running manager for the offering. H.C. Wainwright & Co. acted as lead manager for the offering.

The offering was led by Guggenheim Securities and UBS Investment Bank as joint book-runners, with Mizuho also serving as book-runner and H.C. Wainwright as lead manager. The involvement of multiple major investment banks suggests institutional investor participation in the financing.

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