Sara Bonstein, a former officer of Insmed Inc, filed a Form 144 notice of proposed sale on November 3, 2026, covering 10,261 shares of Insmed common stock with an aggregate market value of $1,121,629.

Key Highlights

  • Seller: Sara Bonstein, identified in the filing as a former officer of Insmed Inc.
  • Shares proposed for sale: 10,261 shares of Insmed common stock, with an aggregate market value of $1,121,629.
  • Approximate sale date: November 3, 2026, through broker Merrill Lynch, located at 1800 K ST NW, Suite 800, Washington, DC 20006.
  • Acquisition date and source: The 10,261 shares were acquired on October 30, 2026, via stock plan activity from the issuer.
  • Purpose of sale: According to the filing, "Shares were sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units and to cover related broker fees."
  • Shares outstanding: The filing reports 219,380,309 shares of Insmed common stock outstanding.
  • Prior sales: The filing reports nothing to report for securities sold during the past three months.

Insmed Former Officer Bonstein Proposes Sale of RSU-Vesting Shares on NASDAQ

According to the Form 144 notice filed with the U.S. Securities and Exchange Commission, Sara Bonstein, a former officer of Insmed Inc (NASDAQ:INSM), is proposing to sell 10,261 shares of the company's common stock. The filing lists an aggregate market value of $1,121,629 for the proposed sale, with an approximate sale date of November 3, 2026. The transaction is to be executed through Merrill Lynch at 1800 K ST NW, Suite 800, Washington, DC 20006.

The filing discloses that the shares were acquired on October 30, 2026, through stock plan activity from the issuer. The filing's remarks section states that the shares were sold to satisfy tax withholding obligations arising from the vesting of Restricted Stock Units and to cover related broker fees. No securities were sold by Bonstein in the three months preceding this notice, the filing reports.

Insmed Inc is headquartered at 700 US Highway 202/206, Bridgewater, New Jersey 08807. The filing notes 219,380,309 total shares of common stock outstanding. The filing was dated November 3, 2026, and was submitted as a live filing with filer CIK 0001604019.

What Was Disclosed

Insmed former officer Sara Bonstein filed a Form 144 on November 3, 2026, disclosing a proposed sale of 10,261 common shares, valued at $1,121,629 in aggregate, acquired through RSU vesting on October 30, 2026, to satisfy tax withholding obligations and broker fees.