Form 4 Filing for William Lewis

William Lewis, Chair and CEO of INSMED Inc, executed a series of transactions on July 23, 2026, primarily involving the acquisition and disposition of Common Stock. Lewis acquired 6,260 shares at $30.46 and 4,440 shares at $17.16, increasing his post-transaction holdings to 265,318 and 269,758 shares respectively. Concurrently, he disposed of 4,828 shares at a weighted average price of $105.62 and 5,872 shares at a weighted average price of $106.43. These transactions were conducted under a Rule 10b5-1 trading plan. Additionally, options to acquire 6,260 and 4,440 shares of Common Stock were exercised. Post-transaction, Lewis directly holds 259,058 shares. Indirectly, shares are held in trust, totaling 233,924 shares.