X0508 4 2026-02-24 0 0001104506 INSMED Inc INSM 0001870278 Smith Michael Alexander 700 US HIGHWAY 202/206 BRIDGEWATER NJ 08807 0 1 0 0 Chief Legal Officer 1 Common Stock 2026-02-24 4 M 0 20248 17.07 A 76645 D Common Stock 2026-02-24 4 S 0 4852 153.93 D 71793 D Common Stock 2026-02-24 4 S 0 4151 155.06 D 67642 D Common Stock 2026-02-24 4 S 0 15771 156.53 D 51871 D Stock Option (right to buy) 17.07 2026-02-24 4 M 0 20248 0 D 2032-05-11 Common Stock 20248 14282 D This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on November 7, 2025 in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. This is the weighted average sales price representing 4,852 shares sold at prices ranging from $153.47 to $154.46 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request. This is the weighted average sales price representing 4,151 shares sold at prices ranging from $154.47 to $155.45 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request. This is the weighted average sales price representing 15,771 shares sold at prices ranging from $156.00 to $156.86 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request. The options become exercisable based on the following vesting schedule: 25% vest on the first anniversary of the grant date and an additional 12.5% vest on each sixth month anniversary date thereafter through the fourth anniversary of the date of grant. /s/ Michael A. Smith 2026-02-26