SEC Form 4 · accession 0001402051-26-000038

INSMED Inc · INSM

Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗

Reporting owner

William Lewis

Officer — Chair and CEO · Director

Period of report

Jun 25, 2026

Accepted (ET)

Jun 26, 2026 · 4:03 pm EDT

Rule 10b5-1 plan

yes — trade under a plan

Issuer CIK

0001104506

Table I — non-derivative securities

Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock	Jun 25, 2026	M	12,518	$30.46	A	271,435	D
Common Stock	Jun 25, 2026	M	8,880	$17.16	A	280,315	D
Common Stock^F2	Jun 25, 2026	S	12,091	$102.34	D	268,224	D
Common Stock^F3	Jun 25, 2026	S	1,836	$103.10	D	266,388	D
Common Stock^F4	Jun 25, 2026	S	3,723	$104.28	D	262,665	D
Common Stock^F5	Jun 25, 2026	S	2,456	$105.27	D	260,209	D
Common Stock^F6	Jun 25, 2026	S	1,292	$106.27	D	258,917	D
Common Stock	holding	—	—		—	233,924	I	By trust

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Stock Option (right to buy)^F7	$30.46	Jun 25, 2026	M	12,518	D	—	Jan 4, 2028	Common Stock	12,518	12,519	D
Stock Option (right to buy)^F7	$17.16	Jun 25, 2026	M	8,880	D	—	May 17, 2027	Common Stock	8,880	8,880	D

Explanation of responses

F1This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on September 4, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.
F2This is the weighted average sales price representing 12,091 shares sold at prices ranging from $101.78 to $102.77 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.
F3This is the weighted average sales price representing 1,836 shares sold at prices ranging from $102.78 to $103.58 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.
F4This is the weighted average sales price representing 3,723 shares sold at prices ranging from $103.87 to $104.75 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.
F5This is the weighted average sales price representing 2,456 shares sold at prices ranging from $104.90 to $105.88 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.
F6This is the weighted average sales price representing 1,292 shares sold at prices ranging from $105.90 to $106.45 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.
F7The 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.