A statement of changes in beneficial ownership for W. Michael Flanagan, a director at Atrium Therapeutics, Inc., was filed with the SEC on September 22, 2026, reflecting a transaction dated September 18, 2026.

Key Highlights

  • Reporting person: W. Michael Flanagan, identified as a Director of Atrium Therapeutics, Inc.
  • Transaction: 22,812 shares of Common Stock were disposed of (transaction code F) on September 18, 2026, at a price of $8.95 per share.
  • Purpose of disposal: According to the filing, the shares were "withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of restricted stock units."
  • Remaining ownership: Following the transaction, Flanagan directly beneficially owned 31,974 shares of Common Stock.
  • No derivative securities: The filing reports no derivative securities acquired, disposed of, or beneficially owned.

Director Share Withholding at Atrium Therapeutics Following RSU Vesting

According to the filing, Atrium Therapeutics, Inc. (NASDAQ:RNA) is a San Diego-based therapeutics company. W. Michael Flanagan, listed as a director, reported a single non-derivative transaction in which 22,812 shares of Common Stock were disposed of on September 18, 2026. The filing classifies the transaction under code "F," which corresponds to shares withheld by the issuer for tax purposes rather than an open-market sale. The price associated with the withholding was $8.95 per share.

The filing explains that the disposal represented shares withheld by the issuer to satisfy tax withholding obligations arising from the vesting of restricted stock units. This type of transaction is common when equity awards vest and the issuing company retains a portion of shares to cover the recipient's tax liability. Following this withholding, Flanagan's direct beneficial ownership in Atrium Therapeutics Common Stock stood at 31,974 shares, according to the filing. No indirect ownership or derivative securities were reported.

The statement was signed by Brendan Winslow as attorney-in-fact on September 22, 2026, and was filed as an individual, single-reporting-person disclosure. The filing contains no indication that it is an amendment to a previously filed form.

What Was Disclosed

The filing discloses that Director W. Michael Flanagan had 22,812 shares of Atrium Therapeutics Common Stock withheld at $8.95 per share on September 18, 2026, to cover tax obligations from restricted stock unit vesting, leaving him with 31,974 directly owned shares.