Bonstein Sara 4

What Happened
Sara Bonstein, Chief Financial Officer of INSMED Inc. (INSM), sold 8,272 shares on May 13, 2026 at $116.18 per share, generating proceeds of approximately $961,041. The transaction is a sale (S) reported on a Form 4.

Key Details

• Transaction date: 2026-05-13
• Price per share: $116.18; Shares sold: 8,272; Proceeds: ~$961,041
• Transaction type: Open market or private sale (reported as S); sale was to satisfy tax withholding
• Footnote: F1 — shares sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units (RSUs) and to cover related broker fees
• Filing: Form 4 filed 2026-05-15 (filed within the standard reporting window)

Context
This sale was executed to cover tax withholding on RSU vesting—a common, administrative reason for insider sales and not necessarily an indicator of the CFO’s view on the company’s prospects. The filing does not disclose post-transaction share ownership in this summary.