Insmed (INSM) Officer Executes Options, Reports Large 10b5-1 Sales

Rhea-AI Filing Summary

Martina Flammer, M.D., Chief Medical Officer of Insmed Inc. (INSM), reported multiple option exercises and subsequent open-market sales on 09/02/2025 under a 10b5-1 trading plan. The filing shows the exercise of stock options at strike prices ranging from $17.07 to $34.03, converting options into shares (total option exercises listed include 186,943 underlying shares across multiple option grants). Following exercises, the report lists a series of sales on the same date totaling 209,066 shares sold at weighted-average prices between $140.56 and $146.51, with incremental remaining beneficial ownership reported at 83,111 shares after the transactions. The Form 4 notes the 10b5-1 plan was adopted on February 27, 2025, and includes vesting schedules for each option series.

Positive

• Transactions executed under a disclosed 10b5-1 plan (adopted February 27, 2025), providing procedural clarity
• Detailed vesting schedules and option terms are included for each grant, showing exercise/expiration dates

Negative

• Large aggregate sales reported on 09/02/2025 totaling 209,066 shares sold across multiple price ranges
• Significant reduction in beneficial ownership from 269,759 shares before some sales to 83,111 shares after the reported transactions

Insights

Securities Analyst

TL;DR: Officer exercised multiple option tranches and executed sizable sales under a 10b5-1 plan, resulting in a meaningful reduction in reported holdings.

The filing documents coordinated option exercises and open-market sales executed on 09/02/2025 pursuant to a 10b5-1 plan adopted 02/27/2025. Multiple option grants with strike prices between $17.07 and $34.03 were exercised, and numerous sale blocks were reported at weighted-average prices from $140.56 to $146.51. The sequence leaves the reporting person with 83,111 shares beneficially owned after transactions. From an SEC-disclosure standpoint, the filing is complete: it provides execution dates, option vesting schedules, sale volumes, and weighted-average prices with commitments to provide per-price breakdowns on request.

Corporate Governance Expert

TL;DR: Insider activity follows a documented Rule 10b5-1 plan and includes standard option-vesting disclosures.

The Form 4 includes the required explanatory notes: adoption date of the 10b5-1 plan, specific vesting schedules for each option grant, and weighted-average sale prices with ranges. Signature and power-of-attorney exhibit are included. The disclosure meets form completeness criteria and clarifies that sales were effected pursuant to the pre-established plan; no additional assertions about motivation or timing are made in the filing.

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
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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)
09/02/2025

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	09/02/2025		M(1)		13,680	A	$34.03	96,791	D
Common Stock	09/02/2025		M(1)		17,160	A	$26.46	113,951	D
Common Stock	09/02/2025		M(1)		25,710	A	$26.43	139,661	D
Common Stock	09/02/2025		M(1)		38,846	A	$17.07	178,507	D
Common Stock	09/02/2025		M(1)		13,072	A	$19.74	191,579	D
Common Stock	09/02/2025		M(1)		36,555	A	$18.95	228,134	D
Common Stock	09/02/2025		M(1)		23,835	A	$29.13	251,969	D
Common Stock	09/02/2025		M(1)		17,790	A	$25.83	269,759	D
Common Stock	09/02/2025		S(1)		19,066	D	$141.27(2)	250,693	D
Common Stock	09/02/2025		S(1)		5,877	D	$142.03(3)	244,816	D
Common Stock	09/02/2025		S(1)		35,245	D	$143.16(4)	209,571	D
Common Stock	09/02/2025		S(1)		28,063	D	$144.05(5)	181,508	D
Common Stock	09/02/2025		S(1)		63,782	D	$145.33(6)	117,726	D
Common Stock	09/02/2025		S(1)		34,615	D	$146.05(7)	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)	$34.03	09/02/2025		M(1)			13,680	(8)	01/07/2031	Common Stock	13,680	$0	0	D
Stock Option (right to buy)	$26.46	09/02/2025		M(1)			17,160	(8)	05/12/2031	Common Stock	17,160	$0	0	D
Stock Option (right to buy)	$26.43	09/02/2025		M(1)			25,710	(9)	01/06/2032	Common Stock	25,710	$0	8,570	D
Stock Option (right to buy)	$17.07	09/02/2025		M(1)			38,846	(9)	05/11/2032	Common Stock	38,846	$0	25,898	D
Stock Option (right to buy)	$19.74	09/02/2025		M(1)			13,072	(9)	01/05/2033	Common Stock	13,072	$0	13,073	D
Stock Option (right to buy)	$18.95	09/02/2025		M(1)			36,555	(9)	05/11/2033	Common Stock	36,555	$0	73,110	D
Stock Option (right to buy)	$29.13	09/02/2025		M(1)			23,835	(9)	01/04/2034	Common Stock	23,835	$0	39,725	D
Stock Option (right to buy)	$25.83	09/02/2025		M(1)			17,790	(10)	05/13/2034	Common Stock	17,790	$0	53,370	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 19,066 shares sold at prices ranging from $140.56 to $141.51 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 5,877 shares sold at prices ranging from $141.61 to $142.55 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 35,245 shares sold at prices ranging from $142.70 to $143.69 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 28,063 shares sold at prices ranging from $143.70 to $144.63 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. This is the weighted average sales price representing 63,782 shares sold at prices ranging from $144.70 to $145.69 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.

7. This is the weighted average sales price representing 34,615 shares sold at prices ranging from $145.70 to $146.51 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.

8. 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. All options are currently exercisable.

9. 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.

10. The options become exercisable based on the following vesting schedule: 25% vest on the first day of the first month following the first anniversary of the date of grant (the Initial Vesting Date) and 12.5% vest on each sixth month anniversary date thereafter through the fourth anniversary of the Initial Vesting Date.

Remarks:

Exhibit List - Exhibit 24 - Power of Attorney

	/s/ Martina Flammer, M.D., by Michael A. Smith as Attorney-in-fact	09/04/2025
	** 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 transactions did Martina Flammer (INSM) report on Form 4?

Answer: On 09/02/2025 she reported multiple option exercises and open-market sales executed under a 10b5-1 plan, with sales totaling 209,066 shares and remaining beneficial ownership of 83,111 shares.

Were these trades made under a 10b5-1 trading plan?

Answer: Yes. The filing states the transactions were effected pursuant to a 10b5-1 trading plan adopted on February 27, 2025.

What option strike prices and exercise details are disclosed?

Answer: Options exercised had strike prices ranging from $17.07 to $34.03 with various exercise/expiration dates and specified vesting schedules; all applicable options listed became exercisable as described.

What price ranges were the shares sold at?

Answer: Sales are reported as weighted-average blocks with price ranges from $140.56 to $146.51, with specific weighted-average sale prices provided for each block.

How many shares remained beneficially owned after the transactions?

Answer: The filing reports 83,111 shares beneficially owned following the reported transactions.