Press Releases May 26, 2026 04:05 PM

Assembly Biosciences Announces the Closing of its Offering of Common Stock and Pre-Funded Warrants and Full Exercise of the Underwriters’ Option to Purchase Additional Shares

Assembly Biosciences closes $115 million common stock and pre-funded warrant offering to advance clinical pipeline.

By Hana Yamamoto ASMB

Assembly Biosciences has completed a registered public offering of approximately 3.9 million common shares and 415,000 pre-funded warrants, raising gross proceeds of $115 million. The company plans to use the funds to advance clinical development of its therapeutic candidates targeting serious viral and liver diseases and for general corporate purposes.

Assembly Biosciences Announces the Closing of its Offering of Common Stock and Pre-Funded Warrants and Full Exercise of the Underwriters’ Option to Purchase Additional Shares
ASMB

Key Points

  • The offering included the full exercise of underwriters' 566,040 share option, demonstrating strong investor demand.
  • Proceeds will primarily fund clinical development efforts for therapies addressing hepatitis B, hepatitis delta, herpesvirus, and cholestatic liver diseases.
  • The company is backed by collaborations and equity investments including a partnership with Gilead Sciences, which supports its developmental pipeline.

SOUTH SAN FRANCISCO, Calif., May 26, 2026 (GLOBE NEWSWIRE) -- 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 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.

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.

A shelf registration statement relating to the securities sold in the offering was filed with the Securities and Exchange Commission (SEC) and was declared effective on March 27, 2026. A preliminary prospectus supplement and a final prospectus supplement relating to the offering were filed with the SEC and are available on the SEC’s website at www.sec.gov. Copies of the preliminary prospectus supplement and final prospectus supplement may be obtained by contacting Guggenheim Securities, LLC, Attention: Equity Syndicate Department, 330 Madison Avenue, 8th Floor, New York, New York 10017, by telephone at (212) 518-9544, or by email at [email protected]; or UBS Securities LLC, Attention: Prospectus Department, UBS Investment Bank, 11 Madison Avenue, New York, New York 10010 or by email at [email protected].

This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Assembly Biosciences

Assembly Biosciences is a biotechnology company dedicated to the development of innovative small-molecule therapeutics designed to change the path of serious viral and liver diseases and improve the lives of patients worldwide. Led by an accomplished team of leaders in viral and liver diseases, Assembly Bio is committed to improving outcomes for patients struggling with the serious, chronic impacts of herpesvirus, hepatitis delta virus (HDV) infections, cholestatic liver diseases and hepatitis B virus (HBV).

Forward-Looking Statements
The information in this press release contains forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to materially differ. These forward-looking statements include statements about the offering, including the expected use of proceeds therefrom. These risks and uncertainties include: Assembly Bio’s ability to realize the potential benefits of its collaboration with Gilead Sciences, Inc. (Gilead), including all financial aspects of the collaboration and equity investments; Assembly Bio’s ability to initiate and complete clinical studies involving its therapeutic product candidates, including studies contemplated by Assembly Bio’s collaboration with Gilead, in the currently anticipated timeframes or at all; safety and efficacy data from clinical or nonclinical studies may not warrant further development of Assembly Bio’s product candidates; clinical and nonclinical data may not differentiate Assembly Bio’s product candidates from other companies’ candidates; Assembly Bio’s ability to maintain financial resources necessary to continue its research activities, clinical studies and other business operations; potential effects of changes in government regulation; results of nonclinical studies may not be representative of disease behavior in a clinical setting and may not be predictive of the outcomes of clinical studies; and other risks identified from time to time in Assembly Bio’s reports filed with the U.S. Securities and Exchange Commission (the SEC). You are urged to consider statements that include the words may, will, would, could, should, might, believes, hopes, estimates, projects, potential, expects, plans, anticipates, intends, continues, forecast, designed, goal or the negative of those words or other comparable words to be uncertain and forward-looking. Assembly Bio intends such forward-looking statements to be covered by the safe harbor provisions contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. More information about Assembly Bio’s risks and uncertainties are more fully detailed under the heading “Risk Factors” in Assembly Bio’s filings with the SEC, including its most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. Except as required by law, Assembly Bio assumes no obligation to update publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

Contacts:
Investors:
Patrick Till
Meru Advisors
(484) 788-8560
[email protected]

Media:
Jamie Strachota
Sam Brown Healthcare Communications, Inc.
(703) 819-7647
[email protected]


Risks

  • Clinical trials may not produce positive or differentiating safety and efficacy data to support further development.
  • Potential delays or inability to initiate or complete clinical studies as anticipated could impact business plans.
  • Regulatory changes or challenges may affect research, approval, and commercialization timelines.

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