INSMED (INSM) Chief Legal Officer sells 640 shares to cover tax withholding

Rhea-AI Filing Summary

INSMED Inc's Chief Legal Officer reports a routine share sale related to equity compensation. On 02/03/2026, Michael Alexander Smith sold 640 shares of INSMED common stock at $156.27 per share. The filing explains the shares were sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units and to cover related broker fees. After this transaction, he directly beneficially owned 56,397 shares of common stock.

Insights

Insider transactions analyst

Small, routine tax-withholding sale by INSMED's Chief Legal Officer.

The filing shows Chief Legal Officer Michael Alexander Smith sold 640 shares of INSMED common stock on February 3, 2026 at $156.27 per share. The transaction code is "S," and ownership remains direct after the sale with 56,397 shares reported as beneficially owned.

A footnote states the sale was made to satisfy tax withholding obligations upon vesting of Restricted Stock Units and to cover broker fees. Such tax-related sales are common around equity vesting and generally administrative rather than strategic. The transaction size is modest relative to the reported remaining holdings.

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

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

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)
02/03/2026

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	02/03/2026		S(1)		640	D	$156.27	56,397	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

Explanation of Responses:

1. Shares sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units and to cover related broker fees.

Remarks:

	/s/ Michael A. Smith	02/04/2026
	** 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 transaction did INSM Chief Legal Officer report on February 3, 2026?

The Chief Legal Officer reported selling 640 shares of INSMED common stock on February 3, 2026 at $156.27 per share. This was a non-derivative transaction coded as a sale and left him holding 56,397 shares directly after the transaction.

Why did the INSM Chief Legal Officer sell 640 shares of common stock?

The shares were sold to satisfy tax withholding obligations related to vesting Restricted Stock Units and to cover associated broker fees. The footnote clarifies this was a tax-related sale tied to equity compensation, rather than a discretionary open-market liquidation.

How many INSM shares does the reporting person own after this Form 4 transaction?

After the reported sale, the Chief Legal Officer beneficially owned 56,397 shares of INSMED common stock directly. This figure reflects his holdings following the 640-share sale executed on February 3, 2026 at $156.27 per share.

What was the price per share for the INSM insider sale on February 3, 2026?

The 640 INSMED common shares were sold at $156.27 per share. This price is disclosed in the non-derivative transaction table, alongside the sale code and the updated beneficial ownership total of 56,397 directly held shares after the transaction.

Does the Form 4 show any INSM derivative securities transactions for the insider?

The Form 4 includes a section for derivative securities but shows no derivative transactions reported for this date. The only disclosed activity is the non-derivative sale of 640 shares of common stock related to tax withholding and broker fee coverage.