Dyne Therapeutics, Inc. SEC Filings

Dyne Therapeutics (DYN) filed its Q3 2025 10‑Q, reporting higher cash and continued R&D investment. Cash and cash equivalents were $573.6 million, with marketable securities of $218.3 million. Total assets reached $867.1 million. The company posted a Q3 net loss of $108.0 million ($0.76 per share) on operating expenses of $113.9 million, driven by research and development of $97.2 million and general and administrative of $16.7 million.

To strengthen liquidity, Dyne completed a public offering for net proceeds of $215.8 million and sold $140.6 million via its at‑the‑market program year‑to‑date. It also drew $100.0 million under a term loan with Hercules, due July 1, 2030, bearing interest at the prime rate (floor 7.50%) plus 2.45%. Long‑term debt, net, was $99.1 million. Shares outstanding were 142.6 million at quarter‑end.

Program updates include FDA Breakthrough Therapy Designation for z‑basivarsen (DM1) and initiation of a registrational expansion cohort in ACHIEVE. For z‑rostudirsen (DMD), the DELIVER 20 mg/kg Q4W registrational expansion cohort completed enrollment, with data planned in December 2025. Subsequent to quarter‑end, Dyne committed at least $25.5 million through March 2027 under a CMO manufacturing agreement.

Dyne Therapeutics, Inc. (DYN) director Brian S. Posner received a stock option grant on 10/01/2025 for 70,000 shares with an exercise price of $12.50. The option is exercisable for underlying common stock and shows 70,000 shares beneficially owned following the grant, reported as direct ownership. The option vests over three years in equal monthly installments through 10/01/2028, giving the director continuing equity alignment over that period. The Form 4 was signed on 10/02/2025 by an attorney-in-fact on behalf of the reporting person.

Brian S. Posner filed an SEC Form 3 as an initial statement of beneficial ownership for Dyne Therapeutics, Inc. (DYN). The event date is 10/01/2025 and the filing reports direct beneficial ownership of 8,500 shares of the issuer's common stock. The form identifies Mr. Posner as a Director and was signed on behalf of the reporting person by Ron Caponigro, Attorney-in-Fact on 10/02/2025. The filing includes a listed address in Waltham, MA and references a Power of Attorney (Exhibit 24.1).

Dyne Therapeutics insider sale tied to RSU vesting. John Cox, CEO & President and a director, reported on Form 4 an automatic sale of 2,640 shares of Dyne Therapeutics common stock on 09/05/2025 at a price of $13.41 per share to satisfy tax withholding obligations arising from the vesting of restricted stock units granted December 4, 2024. After the sale, the filing shows the Reporting Person beneficially owned 199,539 shares directly and has 72,000 shares held indirectly in four trusts for children.

The filing discloses the sale was pursuant to a binding RSU agreement consistent with a Rule 10b5-1 affirmative defense and that 2,640 shares were matchable under Section 16(b) to a 100,000-share purchase on 07/14/2025. The Reporting Person paid the issuer $11,565.07 representing the profit deemed realized under Section 16(b). The report was signed by an attorney-in-fact on 09/09/2025.

Insider sales to satisfy RSU tax withholding reduced Johanna Friedl-Naderer's direct holdings in Dyne Therapeutics (DYN). On 09/04/2025 she reported automatic sales of 894 shares at a weighted average price of $13.27 (transactions ranged $13.08–$13.50) tied to RSUs that vested from a September 3, 2024 grant. On 09/05/2025 she reported automatic sales of 144 shares at $13.41 related to RSUs from a December 4, 2024 grant.

After these transactions her reported beneficial ownership declined from 95,017 to 94,873 shares. The filings state the sales were automatic to satisfy tax withholding and executed under a binding arrangement consistent with a Rule 10b5-1 plan; 74,514 RSUs remain unvested.

Dyne Therapeutics insider sale by Chief Medical Officer Kerr Douglas: On 09/04/2025 and 09/05/2025 Mr. Douglas reported automatic sales of common stock to satisfy tax withholding for vested restricted stock units. A total of 4,425 shares were sold (3,552 shares on 09/04 at a weighted-average price of $13.27 and 873 shares on 09/05 at $13.41). These sales were executed under binding RSU agreements consistent with Rule 10b5-1 affirmative defense and are described as automatic, not discretionary. After the reported transactions the reporting person beneficially owned 88,390 shares, which includes 74,625 unvested RSUs.

Dyne Therapeutics Form 144 summary: This notice reports a proposed sale of 2,640 shares of Dyne common stock through Stifel Nicolaus, with an aggregate market value of $35,404.00 and an approximate sale date of 09/05/2025. The filer acquired 9,081 shares as restricted stock units from the issuer on 09/04/2025 and lists the acquisition payment type as equity compensation. The filing also discloses a prior sale by John Cox of 4,060 shares on 06/05/2025 for gross proceeds of $54,186.00. The company has 142,263,740 shares outstanding, making the proposed sale a very small fraction of total shares. The filer certifies they have no undisclosed material adverse information about the issuer.

Dyne Therapeutics reported a Form 144 notice showing a proposed sale of 4,552 shares of Common Stock on 09/04/2025 through Stifel Nicolaus & Company on Nasdaq with an aggregate market value of $60,402. The shares were acquired as Restricted Stock Units from the issuer on 09/03/2025 (11,875 units) and 09/04/2025 (3,000 units), with payment noted as cash. The filer also disclosed a prior sale of 1,342 shares on 06/05/2025 yielding $17,911. The notice includes the seller's representation that no undisclosed material adverse information is known.