X0508 4 2026-01-06 0 0001104506 INSMED Inc INSM 0001796960 Flammer Martina M.D. 700 US HIGHWAY 202/206 BRIDGEWATER NJ 08807 0 1 0 0 Chief Medical Officer 1 Common Stock 2026-01-06 4 M 0 8570 26.43 A 103324 D Common Stock 2026-01-06 4 S 0 4783 173.47 D 98541 D Common Stock 2026-01-06 4 S 0 2830 174.21 D 95711 D Common Stock 2026-01-06 4 S 0 957 175.01 D 94754 D Common Stock 2026-01-06 4 S 0 1615 173.33 D 93139 D Common Stock 2026-01-07 4 S 0 1434 175.84 D 91705 D Common Stock 2026-01-08 4 S 0 1660 173.87 D 90045 D Common Stock 2026-01-08 4 S 0 3251 174.17 D 86794 D Stock Option (right to buy) 26.43 2026-01-06 4 M 0 8570 0 D 2032-01-06 Common Stock 8570 0 D This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on February 27, 2025 in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. This is the weighted average sales price representing 4,783 shares sold at prices ranging from $172.89 to $173.87 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 2,830 shares sold at prices ranging from $173.92 to $174.80 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 957 shares sold at prices ranging from $174.97 to $175.12 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. Shares sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units and to cover related broker fees. This is the weighted average sales price representing 1,434 shares sold at prices ranging from $175.72 to $176.00 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 1,660 shares sold at prices ranging from $173.87 to $173.90 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 became exercisable based on the following vesting schedule: 25% vested on the first anniversary of the grant date and an additional 12.5% vested on each sixth month anniversary date thereafter through the fourth anniversary of the date of grant. /s/ Martina Flammer, M.D., by Michael A. Smith as Attorney-in-fact 2026-01-08