Form 4 Filing for William Lewis

William Lewis, Chair and CEO of INSMED Inc, executed a series of transactions on April 6, 2026, related to the company's Common Stock. Lewis acquired 6,259 shares at $30.46 and 4,440 shares at $17.16, both under a 10b5-1 trading plan. Additionally, Lewis disposed of shares in several transactions: 787 shares at a weighted average of $161.73, 8,478 shares at a weighted average of $163.23, and 1,434 shares at a weighted average of $164.01. These sales were also conducted under the aforementioned 10b5-1 trading plan. Following these transactions, Lewis directly holds 301,185 shares. In a separate holding, 233,924 shares are held indirectly by the Katie Procter Dynasty Trust. Derivative transactions include the exercise of stock options for 6,259 shares and 4,440 shares, with the options vesting over time according to a specified schedule.