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 (Nasdaq: ASMB) closed its underwritten registered offering of 3,924,624 common shares at $26.50 per share, including full exercise of underwriters’ option for 566,040 additional shares.

Rhea-AI Summary

Assembly Biosciences (Nasdaq: ASMB) closed its underwritten registered offering of 3,924,624 common shares at $26.50 per share, including full exercise of underwriters’ option for 566,040 additional shares.

The company also sold pre-funded warrants for 415,000 shares, raising approximately $115 million in gross proceeds to fund clinical pipeline development and general corporate purposes.

Positive

• Approximately $115.0 million in gross proceeds raised from the offering
• Full exercise of underwriters’ option for 566,040 additional shares
• Proceeds earmarked to fund clinical development of pipeline candidates

Negative

• Issuance of 3,924,624 new shares creates potential shareholder dilution
• Pre-funded warrants for 415,000 shares may add further future dilution

Argus May 27 session

-4.70% close to close Open Argus

Details

News Market Reaction – ASMB

In the May 27 session, ASMB declined 4.70%, reflecting a moderate negative market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

This announcement closes a previously priced underwritten offering, confirming 3,924,624 common shar...

Analysis

This announcement closes a previously priced underwritten offering, confirming 3,924,624 common shares sold, full exercise of the 566,040-share underwriters’ option, 415,000 pre-funded warrant shares and gross proceeds of $115.0M. The company indicated proceeds will support clinical development and general corporate purposes, complementing earlier disclosures of $226.6M in cash and a funding runway into 2028. Investors may track future use of the $400,000,000 shelf, the $100,000,000 ATM program and progress of ABI-6250 and other pipeline candidates.

Key Figures

Shares offered: 3,924,624 shares Offering price: $26.50 per share Underwriters’ option: 566,040 shares +4 more

Shares offered

3,924,624 shares

Total common stock in underwritten offering including option exercise

Offering price

$26.50 per share

Common stock offering price in this underwritten deal

Underwriters’ option

566,040 shares

Additional common shares purchased via fully exercised option

Pre-funded warrants

415,000 shares

Aggregate common shares underlying pre-funded warrants sold

Pre-funded warrant price

$26.499 per warrant

Per pre-funded warrant, reflecting share price less exercise price

Warrant exercise price

$0.001 per share

Exercise price for each pre-funded warrant share

Gross proceeds

$115.0 million

Aggregate gross proceeds before fees and expenses

Previous Offering Reports

1 past event · Latest: May 22

Same Type 1 event

1. May 22

   Equity offering pricing

   24h Move

   +6.9%

   Priced underwritten common stock and pre-funded warrant offering for pipeline funding.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

pre-funded warrants, underwritten registered offering, shelf registration statement, prospectus supplement

4 terms

pre-funded warrants financial

"Assembly Bio sold to a certain existing investor pre-funded warrants to purchase up to an aggregate of 415,000 shares..."

Pre-funded warrants are financial instruments that give investors the right to purchase a company's stock at a set price, but with most or all of the purchase price paid upfront. They function like a coupon or gift card for stock, allowing investors to buy shares later at a fixed price, which can be beneficial if they want to avoid future price increases. This makes them important for investors seeking flexibility and certainty in their investment plans.

underwritten registered offering financial

"announced the closing of its previously announced underwritten registered offering of 3,924,624 shares..."

An underwritten registered offering is a public sale of a company’s securities that has been officially filed with regulators and is sold through one or more investment banks that agree to buy the securities and resell them to investors. Think of it like a store hiring a wholesaler who guarantees to buy the stock on the shelf so the store can raise cash immediately; for investors it signals structured distribution but can dilute existing shares and affect market price depending on size and demand.

shelf registration statement regulatory

"A shelf registration statement relating to the securities sold in the offering was filed with the Securities and Exchange Commission..."

A shelf registration statement is a document a company files with regulators that allows it to sell shares or bonds quickly when it’s a good time to raise money. It’s like having a pre-approved plan ready so the company can act fast without going through lengthy paperwork each time they want to sell, making fundraising more flexible.

prospectus supplement regulatory

"A preliminary prospectus supplement and a final prospectus supplement relating to the offering were filed with the SEC..."

A prospectus supplement is an additional document provided alongside a company's main offering details, offering updated or extra information about a specific financial product being sold. It helps investors understand the latest terms, risks, and details of the investment, similar to how an update or revision clarifies or expands on original instructions, ensuring they have current and complete information before making a decision.

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

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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 GSEquityProspectusDelivery@guggenheimpartners.com; or UBS Securities LLC, Attention: Prospectus Department, UBS Investment Bank, 11 Madison Avenue, New York, New York 10010 or by email at ol-prospectus-request@ubs.com.

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
investor_relations@assemblybio.com

Media:
Jamie Strachota
Sam Brown Healthcare Communications, Inc.
(703) 819-7647
ASMBMedia@sambrown.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Assembly Biosciences (Nasdaq: ASMB) announce on May 26, 2026 about its stock offering?

Assembly Biosciences announced the closing of its underwritten registered offering of common stock and pre-funded warrants. According to Assembly Bio, the deal included 3,924,624 common shares and pre-funded warrants, with aggregate gross proceeds of approximately $115.0 million before fees and expenses.

How many shares did ASMB issue in the May 2026 stock offering and at what price?

Assembly Biosciences issued 3,924,624 shares of common stock at $26.50 per share. According to Assembly Bio, this total includes 566,040 additional shares sold from the underwriters’ fully exercised option to purchase extra common stock in the offering.

What are the details of Assembly Biosciences’ pre-funded warrants in the May 2026 ASMB offering?

Assembly Biosciences sold pre-funded warrants to purchase up to 415,000 shares of common stock. According to Assembly Bio, each warrant was priced at $26.499, reflecting the $26.50 common share price minus a $0.001 per share exercise price for the warrants.

How much capital did Assembly Biosciences (ASMB) raise and how will it use the proceeds?

Assembly Biosciences raised approximately $115.0 million in gross proceeds from the offering. According to Assembly Bio, net proceeds are intended to fund clinical development of its pipeline candidates targeting viral and liver diseases and for general corporate purposes.

What does the May 2026 stock and warrant offering mean for ASMB shareholders?

The offering increases Assembly Biosciences’ capital base but adds new shares and potential warrant exercises. According to Assembly Bio, the funds will support clinical pipeline development, while the 3,924,624 new shares and 415,000 underlying warrant shares may dilute existing ownership.

Who managed Assembly Biosciences’ May 2026 underwritten offering of ASMB shares and warrants?

Guggenheim Securities and UBS Investment Bank served as joint book-running managers for the offering. According to Assembly Bio, Mizuho acted as an additional book-running manager, while H.C. Wainwright & Co. served as lead manager on the transaction.

Was the May 2026 ASMB securities offering conducted under an effective SEC registration statement?

Yes, the offering was conducted under an effective shelf registration statement filed with the SEC. According to Assembly Bio, the registration statement covering these securities was declared effective on March 27, 2026, enabling the registered underwritten offering to proceed.