Kathleen P. Gallagher, Chief Executive Officer and President of Atrium Therapeutics, Inc., filed a Form 4 on September 22, 2026, reporting a disposition of common stock on September 18, 2026, related to the vesting of restricted stock units.

Key Highlights

  • Reporting person: Kathleen P. Gallagher, serving as Chief Executive Officer and President, and also listed as a Director.
  • Transaction date: September 18, 2026, involving common stock of Atrium Therapeutics, Inc. (NASDAQ:RNA).
  • Shares disposed: 11,632 shares of common stock were withheld at a price of $8.95 per share.
  • Purpose of disposition: According to the filing, the shares represent amounts "withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of restricted stock units."
  • Beneficial ownership after transaction: Gallagher directly held 119,729 shares of common stock following the reported transaction.
  • Ownership form: All reported holdings are direct.

Atrium Therapeutics CEO Reports RSU Tax Withholding Disposition

According to the Form 4 filed with the U.S. Securities and Exchange Commission, Kathleen P. Gallagher, who serves as Chief Executive Officer, President, and Director of Atrium Therapeutics, Inc. (NASDAQ:RNA), reported a single non-derivative securities transaction. The transaction, coded "F" under Instruction 8, involved 11,632 shares of common stock disposed of on September 18, 2026, at a price of $8.95 per share.

The filing discloses that the disposition was not a market sale. Rather, the shares were withheld by the issuer to cover tax withholding obligations arising from the vesting of restricted stock units, as stated in the explanation of responses. This type of transaction is a standard mechanism in equity compensation arrangements, in which a company retains a portion of vesting shares on behalf of the recipient to satisfy applicable tax requirements.

Following the reported transaction, Gallagher's directly held beneficial ownership of Atrium Therapeutics common stock stood at 119,729 shares, according to the filing. No derivative securities transactions were reported in Table II. The Form 4 was signed by Brendan Winslow as Attorney-in-Fact and dated September 22, 2026.

What Was Disclosed

Atrium Therapeutics CEO and President Kathleen P. Gallagher disclosed the withholding of 11,632 shares of common stock at $8.95 per share on September 18, 2026, to satisfy tax obligations tied to RSU vesting, leaving her with 119,729 directly held shares.