[Form 4] INSMED Inc Insider Trading Activity

Rhea-AI Filing Summary

Insmed Inc. (INSM) reported insider transactions by its Chief Medical Officer on 11/11/2025. The officer exercised stock options for 12,949 shares at $17.07 and 18,277 shares at $18.95 (transaction code M), then sold shares in open-market trades (transaction code S) under a Rule 10b5-1 plan adopted on February 27, 2025.

Sales were executed at weighted average prices of $188.38 for 5,467 shares (range $187.93–$188.90), $189.36 for 12,224 shares (range $188.90–$189.88), $190.33 for 10,622 shares (range $189.92–$190.90), and $191.04 for 2,913 shares (range $190.94–$191.14). Following these transactions, the officer reported 83,111 shares beneficially owned directly. The disclosed options carry expirations on 05/11/2032 and 05/11/2033, with vesting at 25% on the first anniversary and 12.5% each six months through the fourth anniversary.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Flammer Martina M.D.

(Last) (First) (Middle)

700 US HIGHWAY 202/206

(Street)

BRIDGEWATER NJ 08807

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
INSMED Inc [ INSM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Medical Officer

3. Date of Earliest Transaction (Month/Day/Year)
11/11/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	11/11/2025		M(1)		12,949	A	$17.07	96,060	D
Common Stock	11/11/2025		M(1)		18,277	A	$18.95	114,337	D
Common Stock	11/11/2025		S(1)		5,467	D	$188.38(2)	108,870	D
Common Stock	11/11/2025		S(1)		12,224	D	$189.36(3)	96,646	D
Common Stock	11/11/2025		S(1)		10,622	D	$190.33(4)	86,024	D
Common Stock	11/11/2025		S(1)		2,913	D	$191.04(5)	83,111	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$17.07	11/11/2025		M(1)			12,949	(6)	05/11/2032	Common Stock	12,949	$0	12,949	D
Stock Option (right to buy)	$18.95	11/11/2025		M(1)			18,277	(6)	05/11/2033	Common Stock	18,277	$0	54,833	D

Explanation of Responses:

1. 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.

2. This is the weighted average sales price representing 5,467 shares sold at prices ranging from $187.93 to $188.90 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.

3. This is the weighted average sales price representing 12,224 shares sold at prices ranging from $188.90 to $189.88 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.

4. This is the weighted average sales price representing 10,622 shares sold at prices ranging from $189.92 to $190.90 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.

5. This is the weighted average sales price representing 2,913 shares sold at prices ranging from $190.94 to $191.14 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.

6. 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.

Remarks:

	/s/ Martina Flammer, M.D., by Michael A. Smith as Attorney-in-fact	11/13/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider activity did INSM report?

The Chief Medical Officer exercised options and sold shares on 11/11/2025 under a Rule 10b5-1 plan.

How many options were exercised and at what prices for INSM?

Options were exercised for 12,949 shares at $17.07 and 18,277 shares at $18.95.

What were the INSM share sale amounts and prices?

Sales included 5,467 at $188.38, 12,224 at $189.36, 10,622 at $190.33, and 2,913 at $191.04 (weighted averages with stated ranges).

What is the officer’s INSM beneficial ownership after the transactions?

Reported direct beneficial ownership is 83,111 shares after the transactions.

Was the INSM trading under a 10b5-1 plan?

Yes. The transactions were effected pursuant to a Rule 10b5-1 plan adopted on February 27, 2025.

What are the option expiration dates and vesting terms?

Option expirations are 05/11/2032 and 05/11/2033; vesting is 25% at one year then 12.5% every six months through the fourth year.