INSMED (INSM) CLO exercises options and sells 19,638 shares under 10b5-1 plan

Rhea-AI Filing Summary

INSMED Inc Chief Legal Officer Michael Alexander Smith exercised stock options and sold shares in a pre-planned transaction. On March 30, 2026, he exercised options for 19,638 shares of common stock at exercise prices of $17.07 and $27.89 per share. The same day, he sold 19,638 shares of common stock at $150.98 per share under a Rule 10b5-1 trading plan adopted on November 7, 2025. After these transactions, he directly owned 51,871 shares of INSMED common stock.

Insider Trade Summary 10b5-1

Net Seller: 19,638 shares ($2,964,945)

Net Sell 5 txns

Insider Smith Michael Alexander

Role Chief Legal Officer

Sold 19,638 shs ($2.96M)

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy)	5,649	$0.00	--
Exercise	Stock Option (right to buy)	13,989	$0.00	--
Exercise	Common Stock	5,649	$17.07	$96K
Exercise	Common Stock	13,989	$27.89	$390K
Sale	Common Stock	19,638	$150.98	$2.96M

Holdings After Transaction: Stock Option (right to buy) — 8,633 shares (Direct); Common Stock — 57,520 shares (Direct)

Footnotes (1)

1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on November 7, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. The options become exercisable based on the following vesting schedule: 25% vest on the first anniversary of the grant date and an additional 12.5% vest on each sixth month anniversary date thereafter through the fourth anniversary of the date of grant. 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.

Key Figures

Options exercised: 19,638 shares Exercise prices: $17.07 and $27.89 per share Shares sold: 19,638 shares +3 more

6 metrics

Options exercised 19,638 shares Stock options converted to common stock on March 30, 2026

Exercise prices $17.07 and $27.89 per share Option exercise prices for INSMED common stock

Shares sold 19,638 shares Open-market sale of common stock on March 30, 2026

Sale price $150.98 per share Price for INSMED common stock sale

Shares owned after 51,871 shares Direct holdings after reported transactions

10b5-1 plan adoption date November 7, 2025 Date trading plan was adopted for these transactions

Key Terms

Rule 10b5-1 trading plan, Stock Option (right to buy, open-market sale, vesting schedule, +1 more

5 terms

Rule 10b5-1 trading plan regulatory

"This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on November 7, 2025"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

Stock Option (right to buy financial

"security_title": "Stock Option (right to buy)""

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.

vesting schedule financial

"The options become exercisable based on the following vesting schedule: 25% vest on the first anniversary"

A vesting schedule is a timeline that determines when someone gains full ownership of certain benefits, such as company stock or retirement contributions. Think of it like earning the right to own a gift gradually over time, rather than receiving it all at once. It matters to investors because it affects when they can fully access or sell these benefits, influencing their financial planning and decision-making.

Exercise or conversion of derivative security financial

"transaction_code_description": "Exercise or conversion of derivative security""

Form 4 Insider Transactions: What Each Field Means →

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 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)
03/30/2026

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	03/30/2026		M(1)		5,649	A	$17.07	57,520	D
Common Stock	03/30/2026		M(1)		13,989	A	$27.89	71,509	D
Common Stock	03/30/2026		S(1)		19,638	D	$150.98	51,871	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)	$17.07	03/30/2026		M(1)			5,649	(2)	05/11/2032	Common Stock	5,649	$0	8,633	D
Stock Option (right to buy)	$27.89	03/30/2026		M(1)			13,989	(3)	07/08/2031	Common Stock	13,989	$0	18,561	D

Explanation of Responses:

1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on November 7, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.

2. The options become exercisable based on the following vesting schedule: 25% vest on the first anniversary of the grant date and an additional 12.5% vest on each sixth month anniversary date thereafter through the fourth anniversary of the date of grant.

3. 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.

Remarks:

	/s/ Michael A. Smith	03/31/2026
	** 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)

FAQ

What did INSM Chief Legal Officer Michael Alexander Smith report in this Form 4?

Michael Alexander Smith reported exercising stock options for 19,638 shares of INSMED common stock and selling 19,638 shares on March 30, 2026. These actions reflect an exercise-and-sell sequence tied to existing option awards and do not eliminate his remaining share ownership.

At what prices did Michael Alexander Smith exercise and sell INSM shares?

He exercised options at $17.07 and $27.89 per share, then sold 19,638 shares at $150.98 per share. The difference between exercise prices and sale price represents the spread realized on these option-based shares in this pre-planned transaction.

How many INSM shares does Michael Alexander Smith hold after these transactions?

Following the reported transactions, Michael Alexander Smith directly owns 51,871 shares of INSMED common stock. This post-transaction holding figure comes from the Form 4 and shows he retains a meaningful equity stake after exercising options and selling some shares.

Were Michael Alexander Smith’s INSM share sales under a Rule 10b5-1 plan?

Yes. A footnote states the transaction was effected under a Rule 10b5-1 trading plan adopted on November 7, 2025. Such plans are established in advance, making the timing of sales more routine and less about short-term market views.

What type of securities did Michael Alexander Smith exercise in this INSM Form 4 filing?

He exercised stock options (right to buy) that converted into 19,638 shares of INSMED common stock. The options carried exercise prices of $17.07 and $27.89 per share and had previously vested according to specified vesting schedules.