[Form 4] Insmed, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Insmed, Inc. (INSM) Chief Legal Officer Michael A. Smith reported transactions on 09/02/2025. Mr. Smith exercised stock options to acquire 12,780 shares at an exercise price of $30.46 and immediately sold multiple blocks of common stock under a Rule 10b5-1 trading plan. The sales totaled 24,252 shares at weighted average prices ranging from $140.58 to $146.04 per share, reducing his reported beneficial ownership from 79,174 shares to 54,902 shares. All exercised options are currently exercisable and the transactions were effected pursuant to a 10b5-1 plan adopted February 27, 2025.

Positive

• Transactions executed under a documented 10b5-1 plan, indicating pre-planned trading and compliance with insider trading rules.
• Full disclosure of weighted average sale prices with commitment to provide per-price breakdowns on request, supporting transparency.

Negative

• Reported beneficial ownership decreased materially from 79,174 shares to 54,902 shares after the transactions.
• Insider sold 24,252 shares in multiple tranches on the same date, representing significant insider monetization.

Insights

Financial Analyst

TL;DR: Insider exercised options and sold shares under a pre-established 10b5-1 plan; notable execution size but routine in structure.

The exercise of 12,780 options at $30.46 followed by sales of 24,252 shares generated cash proceeds at prices between $140.58 and $146.04, materially reducing the reporting person's holdings by approximately 30% of pre-transaction shares. Because the sales were executed under a documented 10b5-1 plan, this suggests pre-planned liquidity rather than ad hoc disposition. The transactions do not, by themselves, indicate operational issues at the company but do increase public float and reflect insider monetization of vested equity.

Corporate Governance Expert

TL;DR: Transactions comply with Rule 10b5-1; transparency is good, but reduced insider stake is noteworthy.

The filing clearly discloses adoption date of the 10b5-1 plan and weighted average sale prices for each sale tranche with undertakings to provide per-price breakdowns on request, which aligns with strong disclosure practices. The reduction in beneficial ownership from 79,174 to 54,902 shares is substantial for a single officer and may modestly alter perceptions of insider alignment with shareholders, although no governance rule violations are indicated.

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^*

Smith Michael Alexander

(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 Legal 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)		12,780	A	$30.46	79,174	D
Common Stock	09/02/2025		S(1)		1,354	D	$141.16(2)	77,820	D
Common Stock	09/02/2025		S(1)		1,100	D	$142.06(3)	76,720	D
Common Stock	09/02/2025		S(1)		7,391	D	$143.16(4)	69,329	D
Common Stock	09/02/2025		S(1)		8,300	D	$144.16(5)	61,029	D
Common Stock	09/02/2025		S(1)		4,944	D	$145.18(6)	56,085	D
Common Stock	09/02/2025		S(1)		1,183	D	$145.89(7)	54,902	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)	$30.46	09/02/2025		M(1)			12,780	(8)	01/04/2028	Common Stock	12,780	$0	0	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 1,354 shares sold at prices ranging from $140.58 to $141.50 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 1,100 shares sold at prices ranging from $141.58 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 7,391 shares sold at prices ranging from $142.70 to $143.63 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.

5. This is the weighted average sales price representing 8,300 shares sold at prices ranging from $143.72 to $144.71 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 4,944 shares sold at prices ranging from $144.72 to $145.57 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 1,183 shares sold at prices ranging from $145.75 to $146.04 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.

Remarks:

Exhibit List - Exhibit 24 - Power of Attorney

	/s/ Michael A. Smith	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 the INSM insider report on Form 4?

The filing reports exercise of 12,780 stock options at $30.46 and sales of 24,252 common shares executed on 09/02/2025.

Were the trades made under a Rule 10b5-1 plan for INSM?

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

How did Michael A. Smith's ownership change after the trades?

Beneficial ownership declined from 79,174 shares to 54,902 shares following the reported transactions.

What price ranges were the INSM shares sold at?

Sales were at weighted average prices with ranges from $140.58 to $146.04 per share across tranches; detailed per-price breakdowns are available on request as stated in the filing.

Are the exercised options still exercisable?

Yes. The filing states all options are currently exercisable and describes the original vesting schedule.