Insmed (INSM) chief legal officer sells shares for tax withholding

Rhea-AI Filing Summary

Insmed's chief legal officer reports small share sales tied to tax withholding. Michael Alexander Smith, Chief Legal Officer of Insmed Inc., reported three sales of common stock on January 6–8, 2026. He sold 1,396 shares at $173.33, 709 shares at $175.07, and 1,053 shares at $174.17. After these transactions, he directly beneficially owned 57,037 shares of Insmed common stock. A footnote explains that the shares were sold to satisfy tax withholding obligations upon the vesting of restricted stock units and to cover related broker fees, indicating the sales were driven by tax requirements rather than discretionary trading.

Insider Trade Summary

Net Seller: 3,158 shares

Net Sell 3 txns

Insider Smith Michael Alexander

Role Chief Legal Officer

Sold 3,158 shs ($549K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,053	$174.17	$183K
Sale	Common Stock	709	$175.07	$124K
Sale	Common Stock	1,396	$173.33	$242K

Holdings After Transaction: Common Stock — 57,037 shares (Direct)

Footnotes (1)

1. F1. Shares sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units and to cover related broker fees.

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Form 4 Insider Transactions: What Each Field Means →

Accepted by SEC EDGAR 01/08/2026 - 05:19 PM Learn about SEC filing dates

FAQ

Who is the insider reporting this Form 4 transaction for INSM?

The reporting person is Michael Alexander Smith, who serves as Chief Legal Officer of Insmed Inc.

What transactions did Insmed (INSM) disclose in this Form 4?

The Form 4 reports three sales of Insmed common stock on January 6, 7, and 8, 2026, each coded as a sale transaction (code S).

How many Insmed shares did the chief legal officer sell and at what prices?

He sold 1,396 shares at $173.33 on January 6, 709 shares at $175.07 on January 7, and 1,053 shares at $174.17 on January 8, 2026.

How many Insmed shares does Michael Alexander Smith hold after these sales?

Following the reported transactions, he beneficially owned 57,037 shares of Insmed common stock in direct ownership.

Why were the Insmed shares sold according to the Form 4 footnote?

The footnote states that the shares were sold to satisfy tax withholding obligations upon the vesting of restricted stock units and to cover related broker fees.

Are the reported Insmed transactions direct or indirect holdings?

The transactions are reported as direct ownership, indicated by the ownership form code D 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
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).

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)
01/06/2026

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	01/06/2026		S(1)		1,396	D	$173.33	58,799	D
Common Stock	01/07/2026		S(1)		709	D	$175.07	58,090	D
Common Stock	01/08/2026		S(1)		1,053	D	$174.17	57,037	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	01/08/2026
	** 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.