INSM director awarded 3,305 RSUs in equity grant

Brennan David R reported acquisition or exercise transactions in this Form 4 filing.

Rhea-AI Filing Summary

Brennan David R reported acquisition or exercise transactions in this Form 4 filing.

INSMED Inc director David R. Brennan reported new equity compensation and existing indirect holdings. He received 3,305 Restricted Stock Units (RSUs), each representing one share of common stock, granted on May 13, 2026 for no consideration. These RSUs vest in full on the first anniversary of the grant date if he remains on the Board and attends at least 75% of Board meetings during the vesting period. After the grant, he directly holds 64,238 shares of common stock and has an additional 60,000 shares held indirectly through his spouse’s revocable trust.

Insider Trade Summary

Grant/Award: 3,305 shares

Grant/Award 2 txns

Insider Brennan David R

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	3,305	$0.00	$0.00
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 64,238 shares (Direct); Common Stock — 60,000 shares (Indirect, By spouse revocable trust)

Footnotes (2)

1. F1. Represents Restricted Stock Units (RSUs), each representing a contingent right to receive one share of Common Stock. The RSUs vest in full on the first anniversary of the grant date (the Vesting Date), provided that the director (a) remains a member of the Board of Directors of the issuer until the earlier of (i) such Vesting Date and (ii) the Company's Annual Shareholder Meeting in the year of such Vesting Date, and (b) attends at least 75% of the meetings of the Board of Directors which take place between the grant date and the first anniversary of the grant date.
2. F2. Each RSU was granted on May 13, 2026, for no consideration.

Key Figures

RSU grant size: 3,305 RSUs Direct shares after grant: 64,238 shares Indirect holdings: 60,000 shares

3 metrics

RSU grant size 3,305 RSUs Granted May 13, 2026, each for no consideration

Direct shares after grant 64,238 shares Common stock directly held by Brennan following RSU grant

Indirect holdings 60,000 shares Common stock held by spouse revocable trust as of May 13, 2026

Key Terms

Restricted Stock Units (RSUs), vesting, grant, award, or other acquisition, revocable trust

4 terms

Restricted Stock Units (RSUs) financial

"Represents Restricted Stock Units (RSUs), each representing a contingent right to receive one share of Common Stock."

Restricted stock units (RSUs) are a type of company promise to give employees shares of stock in the future, usually after certain conditions like working for a set time. They are like a gift promised today that you receive later, which can become valuable if the company's stock price goes up. RSUs matter because they are a way companies reward employees and can be a significant part of compensation.

vesting financial

"The RSUs vest in full on the first anniversary of the grant date (the Vesting Date)."

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

grant, award, or other acquisition financial

"transaction_code_description: Grant, award, or other acquisition"

revocable trust financial

"nature_of_ownership: By spouse revocable trust"

A revocable trust is a legal arrangement where the person who creates it keeps control and can change or cancel the trust at any time, while naming who will manage and receive the assets later. Think of it like a flexible folder for your investments and property that can be relabeled or reworked as circumstances change; it matters to investors because it determines how ownership is recorded, how easily assets transfer on incapacity or death, and whether holdings bypass public probate proceedings.

FAQ

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

What insider transaction did INSM (INSMED Inc) director David R. Brennan report?

Director David R. Brennan reported receiving 3,305 Restricted Stock Units (RSUs) in INSM common stock as a grant on May 13, 2026. This is equity compensation, not an open-market purchase or sale, and increases his potential future share ownership.

How many INSM shares does David R. Brennan hold after this Form 4 filing?

After the RSU grant, David R. Brennan directly holds 64,238 INSM common shares. In addition, 60,000 shares are held indirectly through his spouse’s revocable trust, giving him both direct and indirect exposure to the company’s equity.

What are the vesting conditions for David R. Brennan’s 3,305 INSM RSUs?

The 3,305 RSUs vest in full on the first anniversary of the May 13, 2026 grant date. Vesting requires Brennan to remain on the Board and attend at least 75% of Board meetings during the period before the first anniversary.

Were any INSM shares bought or sold on the market in this Form 4?

No open-market purchases or sales were reported. The Form 4 shows a grant of 3,305 RSUs at no cost and an entry reflecting 60,000 shares held indirectly by a spouse’s revocable trust, rather than a market trade.

How were the 3,305 INSM RSUs granted to David R. Brennan priced?

Each of the 3,305 RSUs was granted for no consideration, meaning Brennan did not pay cash for them. Each RSU represents a contingent right to receive one share of INSM common stock upon satisfying the vesting conditions.

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

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Accepted by SEC EDGAR 05/15/2026 - 04:07 PM EDT Learn about SEC filing dates

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^*

Brennan David R

(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)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/13/2026

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	05/13/2026		A		3,305(1)	A	(2)	64,238	D
Common Stock								60,000	I	By spouse revocable trust

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. Represents Restricted Stock Units (RSUs), each representing a contingent right to receive one share of Common Stock. The RSUs vest in full on the first anniversary of the grant date (the Vesting Date), provided that the director (a) remains a member of the Board of Directors of the issuer until the earlier of (i) such Vesting Date and (ii) the Company's Annual Shareholder Meeting in the year of such Vesting Date, and (b) attends at least 75% of the meetings of the Board of Directors which take place between the grant date and the first anniversary of the grant date.

2. Each RSU was granted on May 13, 2026, for no consideration.

Remarks:

	/s/ David. R. Brennan, by Michael A. Smith as Attorney-in-fact	05/15/2026
	** 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)