Dyne Therapeutics Announces Closing of Upsized Public Offering of Common Stock and Full Exercise by Underwriters of Option to Purchase Additional Shares

Rhea-AI Summary

Dyne Therapeutics (Nasdaq: DYN) closed an upsized underwritten public offering on Dec 11, 2025, selling 21,827,549 shares of common stock at a public offering price of $18.44 per share.

The total gross proceeds to Dyne were approximately $402.5 million before underwriting discounts, commissions and offering expenses. The offering included 2,847,071 shares issued upon full exercise of the underwriters' option to purchase additional shares. All shares were sold by Dyne under a shelf registration on Form S-3 that became effective March 5, 2024.

Positive

• Gross proceeds of approximately $402.5 million
• Underwriters exercised option for 2,847,071 additional shares

Negative

• Issued 21,827,549 new shares, diluting existing shareholders
• Net proceeds reduced by underwriting discounts, commissions and offering expenses

Key Figures

Shares offered 21,827,549 shares Total common shares in this underwritten public offering

Underwriters’ option shares 2,847,071 shares Additional shares from full exercise of underwriters’ option

Offering price $18.44 per share Public offering price for common stock

Gross proceeds $402.5 million Gross proceeds before underwriting discounts and expenses

Market Reality Check

$19.27 Last Close

Volume Volume 9,965,223 is about 3.1x the 20-day average of 3,211,186, indicating elevated trading interest ahead of and around the offering close. high

Technical Shares at $19.69 are trading above the 200-day MA of $13.21, reflecting a sustained uptrend into this financing.

Peers on Argus

DYN gained 6.78% with heavy volume, while close biotech peers showed only modest, mixed moves (e.g., SRPT up 0.41%, MESO up 1.22%, IMCR down 1.93%). This points to a company-specific reaction to the offering rather than a broad sector shift.

Common Catalyst Both DYN and peer SRPT reported capital structure transactions, suggesting funding and balance-sheet actions are a focus in parts of the biotech group.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Dec 09	Offering pricing	Negative	-16.9%	Priced upsized equity offering at $18.44 with significant gross proceeds.
Dec 08	Offering launch	Neutral	+9.5%	Announced proposed $300M equity raise plus $45M underwriter option.
Dec 08	Clinical data	Positive	+9.5%	Reported positive Phase 1/2 DELIVER results with strong dystrophin increases.
Nov 05	Earnings update	Negative	-2.9%	Q3 results with substantial net loss offset by strong cash position and updates.
Nov 03	Investor conferences	Neutral	+6.8%	Planned presentations at multiple healthcare investor conferences.

Pattern Detected

Recent history shows financing announcements often trigger sizable moves, with pricing/closing headlines tending to draw negative reactions, while clinical data and some proposed offerings have been met positively.

Recent Company History

Over the past months, Dyne combined financing activity with key clinical and corporate milestones. In June–July 2025, it executed a series of equity offerings that drew generally negative price reactions. A Nov 5 earnings update highlighted substantial cash and ongoing R&D investment. In early Dec 2025, positive DELIVER trial data and sequential offering announcements led to sharp, but directionally mixed, stock moves. Today’s closing of the upsized offering fits into this ongoing capital-raising phase following clinical progress.

Market Pulse Summary

This announcement confirms the completion of Dyne’s upsized equity raise, including full exercise of the underwriters’ option, resulting in 21,827,549 shares sold at $18.44 and about $402.5 million in gross proceeds before expenses. It follows earlier pricing and proposed-offering releases and comes on the heels of positive clinical data. Investors may track how this larger share count interacts with past volatility around financings and forthcoming clinical or regulatory milestones.

Key Terms

underwritten public offering financial

"closing of its previously announced upsized underwritten public offering of 21,827,549 shares"

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.

gross proceeds financial

"The gross proceeds to Dyne from the offering were approximately $402.5 million"

The total amount of cash a company receives from a financing event or sale before any fees, expenses, taxes or deductions are taken out. Investors watch gross proceeds because it shows the raw scale of new capital being raised—think of it as the paycheck amount before withholdings—which helps assess how much funding is available for operations, growth, debt payoff or how much shareholder dilution might occur once costs are removed.

prospectus supplement regulatory

"The offering was made only by means of a prospectus supplement and accompanying prospectus"

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.

book-running managers financial

"Morgan Stanley, Jefferies, Stifel and Guggenheim Securities acted as joint book-running managers"

Book-running managers are the main banks or financial firms that organize and oversee a company's sale of new stocks or bonds. They help set the price, decide how many to sell, and coordinate the process to make sure everything runs smoothly. Their role is important because they guide the company through the complex process of raising money from investors.

AI-generated analysis. Not financial advice.

WALTHAM, Mass., Dec. 11, 2025 (GLOBE NEWSWIRE) -- Dyne Therapeutics, Inc. (Nasdaq: DYN), a clinical-stage company focused on delivering functional improvement for people living with genetically driven neuromuscular diseases, today announced the closing of its previously announced upsized underwritten public offering of 21,827,549 shares of its common stock at a public offering price of $18.44 per share, which includes 2,847,071 shares issued upon the exercise in full by the underwriters of their option to purchase additional shares of common stock in the offering. The gross proceeds to Dyne from the offering were approximately $402.5 million, before deducting underwriting discounts and commissions and offering expenses payable by Dyne. All of the shares in the offering were sold by Dyne.

Morgan Stanley, Jefferies, Stifel and Guggenheim Securities acted as joint book-running managers for the offering.

The offering was made pursuant to a shelf registration statement on Form S-3 that was previously filed with the Securities and Exchange Commission (“SEC”) on March 5, 2024 and became automatically effective upon filing. The offering was made only by means of a prospectus supplement and accompanying prospectus that form a part of the registration statement. A final prospectus supplement relating to and describing the terms of the offering has been filed with the SEC and may be obtained for free by visiting the SEC’s website at www.sec.gov. Copies of the final prospectus supplement and accompanying prospectus may also be obtained by contacting: Morgan Stanley & Co. LLC, Attention: Prospectus Department, 180 Varick Street, 2nd Floor, New York, NY 10014, or by email at prospectus@morganstanley.com; Jefferies LLC, Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue, New York, NY 10022, by telephone at (877) 821-7388, or by email at Prospectus_Department@Jefferies.com; Stifel, Nicolaus & Company, Incorporated, Attention: Prospectus Department, One Montgomery Street, Suite 3700, San Francisco, CA 94104, by telephone at (415) 364-2720 or by email at syndprospectus@stifel.com; or Guggenheim Securities, LLC, Attention: Equity Syndicate Department, 330 Madison Avenue, 8th Floor, New York, NY 10017, by telephone at (212) 518-9544, or by email at GSEquityProspectusDelivery@guggenheimpartners.com.

This press release shall not constitute an offer to sell, or a 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 Dyne Therapeutics

Dyne Therapeutics is focused on delivering functional improvement for people living with genetically driven neuromuscular diseases. We are developing therapeutics that target muscle and the central nervous system (CNS) to address the root cause of disease. The company is advancing clinical programs for myotonic dystrophy type 1 (DM1) and Duchenne muscular dystrophy (DMD), and preclinical programs for facioscapulohumeral muscular dystrophy (FSHD) and Pompe disease. At Dyne, we are on a mission to deliver functional improvement for individuals, families and communities.

Contacts:
 
Investors

Mia Tobias
ir@dyne-tx.com
781-317-0353

Media

Stacy Nartker
snartker@dyne-tx.com
781-317-1938

FAQ

How many shares did Dyne Therapeutics (DYN) sell in the Dec 11, 2025 offering?

Dyne sold 21,827,549 shares of common stock in the offering.

What were the gross proceeds from Dyne's Dec 11, 2025 offering (DYN)?

The offering generated approximately $402.5 million in gross proceeds before fees and expenses.

How many additional shares were issued when underwriters exercised their option in Dyne's (DYN) offering?

Underwriters exercised their option in full, adding 2,847,071 shares to the offering.

At what price per share did Dyne (DYN) price the Dec 11, 2025 offering?

The public offering price was $18.44 per share.

Will Dyne (DYN) receive all proceeds from the offering closed Dec 11, 2025?

Yes; the press release states that all of the shares in the offering were sold by Dyne, with proceeds before deductions paid to the company.