William Lewis - 02 Jan 2026 Form 4 Insider Report for INSMED Inc (INSM)

Role: Chair and CEO, Director
Signature: /s/ William Lewis, by Michael A. Smith as Attorney-in-fact
Issuer symbol: INSM
Transactions as of: 02 Jan 2026
Net transactions value: $0
Form type: 4
Filing time: 06 Jan 2026, 16:07:17 UTC
Previous filing: 19 Dec 2025
Next filing: 08 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Lewis William	Chair and CEO, Director	700 US HIGHWAY 202/206, BRIDGEWATER	/s/ William Lewis, by Michael A. Smith as Attorney-in-fact	06 Jan 2026	0001402051

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	INSM	Common Stock	Award		+21,172	+7%		325,083	02 Jan 2026	Direct	F1, F2
holding	INSM	Common Stock						233,924	02 Jan 2026	By the Katie Procter Dynasty Trust
holding	INSM	Common Stock						50,500	02 Jan 2026	By the William Lewis Family Legacy Trust

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	INSM	Stock Option (right to buy)	Award	$0	+110,400		$0.000000	110,400	02 Jan 2026	Common Stock	110,400	$177.12	Direct	F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Represents Restricted Stock Units (RSUs), each representing a contingent right to receive one share of Common Stock, granted pursuant to the Company's Amended and Restated 2019 Incentive Plan, as amended. The RSUs vest as follows: 25% on the first day of the first month following the first anniversary of the date of grant (the Initial Vesting Date) and 25% on each anniversary of the Initial Vesting Date until fully vested.
F2	Each RSU was granted on January 2, 2026 for no consideration.
F3	These stock options were granted under the Company's Amended and Restated 2019 Incentive Plan, as amended. The options become exercisable based on the following vesting schedule: 25% vest on the Initial Vesting Date and an additional 12.5% vest every six months thereafter until fully vested.