INSMED legal chief sells shares for tax withholding

INSMED Inc Chief Legal Officer Michael Alexander Smith reported an open-market sale of company stock mainly to cover taxes on vesting equity.

Accepted by SEC EDGAR 06/05/2026 - 04:14 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

INSMED Inc Chief Legal Officer Michael Alexander Smith reported an open-market sale of company stock mainly to cover taxes on vesting equity.

He sold 2,159 shares of Common Stock at $102.27 per share to satisfy tax withholding obligations from vested Restricted Stock Units and related broker fees. After this transaction, he directly holds 39,454 shares, so the sale represents only a portion of his overall stake and is characterized as a tax-related, administrative transaction rather than a discretionary reduction in ownership.

Insider Trade Summary

Net Seller: 2,159 shares

Net Sell 1 txn

Insider Smith Michael Alexander

Role Chief Legal Officer

Sold 2,159 shs ($221K)

Share of Position Sold 5.2%

Type	Security	Shares	Price	Value
Sale	Common Stock	2,159	$102.27	$221K

Holdings After Transaction: Common Stock — 39,454 shares (Direct)

Holdings Before and After: Common Stock, 41,613 to 39,454 shares (Direct)

Other Insiders: 4 other insiders reported open-market sales of this stock in the 30 days up to this filing.

Footnotes (1)

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

Key Figures

Shares sold: 2,159 shares Sale price per share: $102.27 per share Shares held after transaction: 39,454 shares

3 metrics

Shares sold 2,159 shares Common Stock sold in open-market transaction

Sale price per share $102.27 per share Price for 2,159 shares sold

Shares held after transaction 39,454 shares Direct ownership following sale

Key Terms

Restricted Stock Units, tax withholding obligations, open-market sale

3 terms

Restricted Stock Units financial

"upon the vesting of Restricted Stock Units and to cover related broker fees"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax withholding obligations financial

"Shares sold to satisfy tax withholding obligations upon the vesting of Restricted Stock Units"

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did INSM (INSMED Inc) report for Michael Alexander Smith?

INSMED Inc reported that Chief Legal Officer Michael Alexander Smith sold 2,159 shares of Common Stock. The sale was primarily to cover tax withholding obligations related to the vesting of Restricted Stock Units and associated broker fees, rather than a discretionary portfolio decision.

How many INSM shares did Michael Alexander Smith sell and at what price?

Michael Alexander Smith sold 2,159 INSM shares at $102.27 per share. This sale was executed as an open-market transaction and was specifically used to satisfy tax withholding obligations from vested Restricted Stock Units and to pay related broker fees.

How many INSM shares does Michael Alexander Smith hold after this Form 4 transaction?

Following the reported transaction, Michael Alexander Smith directly holds 39,454 shares of INSM Common Stock. This indicates that the 2,159 shares sold to cover tax obligations represent only a fraction of his total direct ownership position in the company.

Was the INSM insider sale by Michael Alexander Smith a discretionary sale or tax-related?

The sale was tax-related. Footnote disclosure states the 2,159 INSM shares were sold to satisfy tax withholding obligations upon vesting of Restricted Stock Units and to cover broker fees, suggesting an administrative transaction instead of a discretionary change in his investment exposure.

What role does Michael Alexander Smith hold at INSMED Inc related to this insider filing?

Michael Alexander Smith serves as Chief Legal Officer at INSMED Inc. His Form 4 filing reflects an open-market sale of 2,159 shares of Common Stock carried out mainly to satisfy tax withholding obligations tied to the vesting of Restricted Stock Units.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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 NEW JERSEY 08807

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/03/2026

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

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

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

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	06/03/2026		S(1)		2,159	D	$102.27	39,454	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	06/05/2026
	** 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.
* Form 4: SEC 1474 (03-26)