Atrium (RNA) CFO Brendan Winslow Withholds 6,742 Shares for Taxes

What Happened
Brendan R. Winslow, CFO of Atrium Therapeutics (RNA), had 6,742 shares withheld by the company to satisfy tax withholding obligations related to the vesting of restricted stock units (RSUs). The filing reports the shares valued at $8.95 each for a total withholding value of $60,341. This was a non‑market disposition (tax withholding), not an open‑market sale.

Key Details

• Transaction date: 2026-09-18; Form 4 filed: 2026-09-22 (filed within the typical 2 business‑day window).
• Withheld: 6,742 shares at $8.95 per share; total value reported: $60,341.
• Nature of transaction: Code F — shares disposed/withheld to satisfy tax liabilities on RSU vesting.
• Footnote: F1 — issuer withheld shares to satisfy tax withholding obligations in connection with RSU vesting.
• Shares owned after transaction: not specified in the information provided in this summary (refer to the full Form 4 for post‑transaction holdings).

Context: Withholding shares for taxes after RSU vesting is routine and does not represent a market sale or an investment decision by the insider. It reduces the insider’s issued share count but is a standard payroll/tax action rather than a bullish or bearish signal.