INSMED CEO exercises options and sells 10,699 shares

INSMED Inc Chair and CEO William Lewis reported a series of equity transactions in company common stock.

Rhea-AI Filing Summary

INSMED Inc Chair and CEO William Lewis reported a series of equity transactions in company common stock. He exercised stock options covering 10,699 shares at exercise prices of $17.16 and $30.46 per share and sold 10,699 shares of common stock in multiple open-market transactions at prices ranging from approximately $116.01 to $118.80 per share. The sales were effected pursuant to a pre-established Rule 10b5-1 trading plan. Lewis also reports 233,924 shares of common stock held indirectly by a trust.

Insights

Equity compensation and governance analyst

CEO executed a planned option exercise-and-sell with no clear thesis change signal.

William Lewis, Chair and CEO of INSMED Inc, exercised stock options for 10,699 common shares at exercise prices of $17.16 and $30.46 per share. On the same July 9, 2026, he sold an equal number of shares in open-market transactions at prices between roughly $116.01 and $118.80 per share.

The filing specifies that these sales were made under a pre-arranged Rule 10b5-1 trading plan adopted on September 4, 2025, which makes the timing more mechanical than discretionary. A separate holding entry shows 233,924 shares held indirectly by trust, and a footnote notes 141 shares acquired through the 2018 Employee Stock Purchase Plan, underscoring that Lewis continues to have substantial equity exposure.

The pattern is a typical compensation-driven exercise-and-sell: options are converted into shares, then sold to realize value, while other direct and indirect holdings remain. Investors may focus on the pre-planned nature of the trades and the continued trust holdings when assessing any sentiment signal from these transactions.

Insider Trade Summary 10b5-1

Exercise and Sale: 10,699 shares ($989K approx. pre-tax spread)

Exercise and Sale 8 txns

Insider Lewis William

Role Chair and CEO

Sold 10,699 shs ($1.26M)

Approx. gross sale proceeds $1.26M

Approx. exercise cost $267K

Approx. pre-tax spread $989K

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy) F1, F6	6,259	$0.00	$0.00
Exercise	Stock Option (right to buy) F1, F6	4,440	$0.00	$0.00
Exercise	Common Stock F1, F2	6,259	$30.46	$191K
Exercise	Common Stock F1	4,440	$17.16	$76K
Sale	Common Stock F1, F3	5,005	$116.55	$583K
Sale	Common Stock F1, F4	2,335	$117.62	$275K
Sale	Common Stock F1, F5	3,359	$118.52	$398K
holding	Common Stock	--	--	--

Holdings After Transaction: Stock Option (right to buy) — 10,700 contracts (Direct); Common Stock — 259,058 shares (Direct); Common Stock — 233,924 shares (Indirect, By trust)

Footnotes (6)

1. F1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on September 4, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.
2. F2. Includes 141 shares acquired through the Company's 2018 Employee Stock Purchase Plan.
3. F3. This is the weighted average sales price representing 5,005 shares sold at prices ranging from $116.01 to $117.00 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 2,335 shares sold at prices ranging from $117.05 to $117.96 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 3,359 shares sold at prices ranging from $118.06 to $118.80 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. 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

Shares sold total: 10,699 shares Weighted average sale price block 1: $116.55 per share Weighted average sale price block 2: $117.62 per share +5 more

8 metrics

Shares sold total 10,699 shares Total INSMED common shares sold in open-market transactions on July 9, 2026

Weighted average sale price block 1 $116.55 per share Weighted average price for 5,005 shares sold, with prices from $116.01 to $117.00

Weighted average sale price block 2 $117.62 per share Weighted average price for 2,335 shares sold, with prices from $117.05 to $117.96

Weighted average sale price block 3 $118.52 per share Weighted average price for 3,359 shares sold, with prices from $118.06 to $118.80

Options exercised at $17.16 4,440 shares at $17.16 Stock options exercised into common stock at a $17.16 per share exercise price

Options exercised at $30.46 6,259 shares at $30.46 Stock options exercised into common stock at a $30.46 per share exercise price

Indirect trust holdings 233,924 shares INSMED common shares reported as held indirectly by trust as of July 9, 2026

ESPP shares included 141 shares Shares acquired through the 2018 Employee Stock Purchase Plan included in reported holdings

Key Terms

Rule 10b5-1 trading plan, weighted average sales price, Stock Option (right to buy), Employee Stock Purchase Plan, +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"

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.

weighted average sales price financial

"This is the weighted average sales price representing 5,005 shares sold at prices"

Stock Option (right to buy) financial

"security_title: Stock Option (right to buy)"

Employee Stock Purchase Plan financial

"Includes 141 shares acquired through the Company's 2018 Employee Stock Purchase Plan"

An employee stock purchase plan is a company program that lets workers buy shares through small payroll deductions, often at a discount to the market price and after a set offering period. Think of it like a workplace savings plan that turns into ownership: it encourages employees to share in the company’s success and can create predictable buying or selling of stock that investors watch because it affects supply, demand and employee incentives.

vested financial

"25% vested on the first anniversary of the grant date and an additional 12.5% vested"

FAQ

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

What did INSM (INSMED Inc) CEO William Lewis report in this Form 4?

William Lewis reported exercising stock options for 10,699 shares of INSMED common stock and selling 10,699 shares in multiple open-market transactions on July 9, 2026 under a Rule 10b5-1 trading plan.

How many INSM shares did William Lewis sell and at what prices?

William Lewis sold a total of 10,699 INSM shares in three transactions at weighted average prices of $116.55, $117.62, and $118.52 per share, with detailed price ranges disclosed in the footnotes.

What options did INSM CEO William Lewis exercise in this Form 4 filing?

He exercised stock options covering 4,440 shares at an exercise price of $17.16 and 6,259 shares at an exercise price of $30.46, converting these options into INSMED common stock.

Was William Lewis’s sale of INSM shares pre-planned under Rule 10b5-1?

Yes. A footnote states the transactions were effected under a Rule 10b5-1 trading plan adopted on September 4, 2025, indicating the sales followed a pre-established schedule rather than ad hoc timing decisions.

How many INSM shares does William Lewis report holding indirectly by trust?

The Form 4 shows an indirect holding of 233,924 INSM common shares held "By trust" as of the July 9, 2026 entry, reflecting a significant position separate from his directly held shares.

Does the INSM Form 4 mention shares from the Employee Stock Purchase Plan?

Yes. A footnote notes that William Lewis’s reported holdings include 141 shares acquired through INSMED’s 2018 Employee Stock Purchase Plan, indicating additional ownership built through the company’s employee purchase program.

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

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Accepted by SEC EDGAR 07/10/2026 - 04:02 PM 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).

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 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
X	Officer (give title below)		Other (specify below)
	Chair and CEO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/09/2026

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	07/09/2026		M(1)		6,259	A	$30.46	265,317(2)	D
Common Stock	07/09/2026		M(1)		4,440	A	$17.16	269,757	D
Common Stock	07/09/2026		S(1)		5,005	D	$116.55(3)	264,752	D
Common Stock	07/09/2026		S(1)		2,335	D	$117.62(4)	262,417	D
Common Stock	07/09/2026		S(1)		3,359	D	$118.52(5)	259,058	D
Common Stock								233,924	I	By 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)	$30.46	07/09/2026		M(1)			6,259	(6)	01/04/2028	Common Stock	6,259	$0	6,260	D
Stock Option (right to buy)	$17.16	07/09/2026		M(1)			4,440	(6)	05/17/2027	Common Stock	4,440	$0	4,440	D

Explanation of Responses:

1. This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on September 4, 2025, in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.

2. Includes 141 shares acquired through the Company's 2018 Employee Stock Purchase Plan.

3. This is the weighted average sales price representing 5,005 shares sold at prices ranging from $116.01 to $117.00 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 2,335 shares sold at prices ranging from $117.05 to $117.96 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 3,359 shares sold at prices ranging from $118.06 to $118.80 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. 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/ William Lewis, by Michael A. Smith as Attorney-in-fact	07/10/2026
	** 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)