Insmed CEO William Lewis Sells $13.5M in Stock Through Planned Trading

Insider Trading Alert: William Lewis, Chair and CEO of Insmed (INSM), executed significant transactions on June 16, 2025, through a pre-planned 10b5-1 trading plan established on September 12, 2024.

Accepted by SEC EDGAR 06/18/2025 - 04:16 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Insider Trading Alert: William Lewis, Chair and CEO of Insmed (INSM), executed significant transactions on June 16, 2025, through a pre-planned 10b5-1 trading plan established on September 12, 2024.

Key Transaction Details:

• Exercised 129,805 stock options at $10.85 per share through the Katie Procter Dynasty Trust
• Sold a total of 5,204 shares directly at weighted average prices ranging from $98.51 to $101.39
• Disposed of 129,805 shares indirectly through the Katie Procter Dynasty Trust at prices ranging from $98.50 to $101.23

Post-Transaction Holdings:

• Direct ownership: 303,554 shares
• Indirect ownership: 233,924 shares (Katie Procter Dynasty Trust)
• Additional indirect ownership: 50,500 shares (William Lewis Family Legacy Trust)

Insider Trade Summary

Exercise and sale activity reported; no spread calculated

Exercise and Sale 10 txns

Insider Lewis William

Role Chair and CEO

Sold 135,009 shs ($13.55M)

Approx. gross sale proceeds $13.55M

Approx. exercise cost $1.41M

Share of Position Sold 20.1%

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy)	129,805	$0.00	$0.00
Sale	Common Stock	442	$98.51	$44K
Sale	Common Stock	1,558	$99.65	$155K
Sale	Common Stock	2,300	$100.70	$232K
Sale	Common Stock	904	$101.39	$92K
Exercise	Common Stock	129,805	$10.85	$1.41M
Sale	Common Stock	7,000	$98.50	$690K
Sale	Common Stock	32,490	$99.51	$3.23M
Sale	Common Stock	48,531	$100.54	$4.88M
Sale	Common Stock	41,784	$101.23	$4.23M
Holding	Common Stock	--	--	--

Holdings After Transaction: Stock Option (right to buy) — 27,355 options (Indirect, By the Katie Procter Dynasty Trust); Common Stock — 303,554 shares (Direct); Common Stock — 233,924 shares (Indirect, By the Katie Procter Dynasty Trust); Common Stock — 50,500 shares (Indirect, By the William Lewis Family Legacy Trust)

Holdings Before and After: Stock Option (right to buy), 157,160 to 27,355 options (Indirect, By the Katie Procter Dynasty Trust); Common Stock, 308,758 to 303,554 shares (Direct); Common Stock, 233,924 to 233,924 shares (Indirect, By the Katie Procter Dynasty Trust)

Other Insiders: 1 other insider reported open-market sales of this stock in the 30 days up to this filing.

Footnotes (10)

1. F1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on September 12, 2024, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.
2. F2. This is the weighted average sales price representing 442 shares sold at prices ranging from $98.08 to $98.94 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
3. F3. This is the weighted average sales price representing 1,558 shares sold at prices ranging from $99.17 to $100.16 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
4. F4. This is the weighted average sales price representing 2,300 shares sold at prices ranging from $100.19 to $101.07 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
5. F5. This is the weighted average sales price representing 904 shares sold at prices ranging from $101.20 to $101.58 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
6. F6. This is the weighted average sales price representing 7,000 shares sold at prices ranging from $97.93 to $98.92 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
7. F7. This is the weighted average sales price representing 32,490 shares sold at prices ranging from $98.94 to $99.93 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
8. F8. This is the weighted average sales price representing 48,531 shares sold at prices ranging from $99.94 to $100.93 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
9. F9. This is the weighted average sales price representing 41,784 shares sold at prices ranging from $100.94 to $101.61 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.
10. F10. 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. All options are currently exercisable.

FAQ

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

How many INSM shares did CEO William Lewis sell on June 16, 2025?

On June 16, 2025, CEO William Lewis sold a total of 5,204 shares directly (in multiple transactions ranging from $98.51 to $101.39 per share) and 129,805 shares indirectly through the Katie Procter Dynasty Trust (at prices ranging from $98.50 to $101.23 per share).

What was the price range of INSM stock sales by William Lewis on June 16, 2025?

The INSM stock sales occurred at various price points ranging from $97.93 to $101.61 per share. The transactions were executed in multiple blocks with weighted average prices including $98.51, $99.65, $100.70, and $101.39 for direct sales, and similar ranges for trust-owned shares.

How many INSM shares does William Lewis still own after the June 16, 2025 transactions?

After the transactions, William Lewis owns 303,554 shares directly, plus indirect ownership of 233,924 shares through the Katie Procter Dynasty Trust and 50,500 shares through the William Lewis Family Legacy Trust, totaling 587,978 shares.

Was INSM CEO William Lewis's stock sale part of a pre-planned trading program?

Yes, the transactions were executed pursuant to a Rule 10b5-1 trading plan that William Lewis adopted on September 12, 2024. This plan was established in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934.

What stock options did INSM's CEO exercise in the June 16, 2025 transaction?

William Lewis exercised 129,805 stock options with a strike price of $10.85 through the Katie Procter Dynasty Trust. These options were originally set to expire on May 19, 2026, and had previously vested according to a schedule of 25% on the first anniversary of grant and 12.5% every six months thereafter.

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

Form 4 Insider Transactions: What Each Field Means →

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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).

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^*

Lewis William

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
06/16/2025

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	06/16/2025		S(1)		442	D	$98.51(2)	308,316	D
Common Stock	06/16/2025		S(1)		1,558	D	$99.65(3)	306,758	D
Common Stock	06/16/2025		S(1)		2,300	D	$100.7(4)	304,458	D
Common Stock	06/16/2025		S(1)		904	D	$101.39(5)	303,554	D
Common Stock	06/16/2025		M(1)		129,805	A	$10.85	363,729	I	By the Katie Procter Dynasty Trust
Common Stock	06/16/2025		S(1)		7,000	D	$98.5(6)	356,729	I	By the Katie Procter Dynasty Trust
Common Stock	06/16/2025		S(1)		32,490	D	$99.51(7)	324,239	I	By the Katie Procter Dynasty Trust
Common Stock	06/16/2025		S(1)		48,531	D	$100.54(8)	275,708	I	By the Katie Procter Dynasty Trust
Common Stock	06/16/2025		S(1)		41,784	D	$101.23(9)	233,924	I	By the Katie Procter Dynasty Trust
Common Stock								50,500	I	By the William Lewis Family Legacy 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
Stock Option (right to buy)	$10.85	06/16/2025		M(1)			129,805	(10)	05/19/2026	Common Stock	129,805	$0	27,355	I	By the Katie Procter Dynasty Trust

Explanation of Responses:

1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on September 12, 2024, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.

2. This is the weighted average sales price representing 442 shares sold at prices ranging from $98.08 to $98.94 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

3. This is the weighted average sales price representing 1,558 shares sold at prices ranging from $99.17 to $100.16 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

4. This is the weighted average sales price representing 2,300 shares sold at prices ranging from $100.19 to $101.07 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

5. This is the weighted average sales price representing 904 shares sold at prices ranging from $101.20 to $101.58 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

6. This is the weighted average sales price representing 7,000 shares sold at prices ranging from $97.93 to $98.92 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

7. This is the weighted average sales price representing 32,490 shares sold at prices ranging from $98.94 to $99.93 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

8. This is the weighted average sales price representing 48,531 shares sold at prices ranging from $99.94 to $100.93 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

9. This is the weighted average sales price representing 41,784 shares sold at prices ranging from $100.94 to $101.61 per share. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer the number of shares sold at each price within the price range upon request.

10. 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. All options are currently exercisable.

Remarks:

	/s/ William Lewis, by Michael A. Smith as Attorney-in-fact	06/18/2025
	** 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.
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