INSMED (INSM) CEO Lewis sells 6,515 shares under Rule 10b5-1 plan

Filing Impact

(Very High)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

INSMED Inc Chair and CEO William Lewis reported an open-market sale of 6,515 shares of Common Stock. The shares were sold at a price of $94.03 per share. After this transaction, he directly holds 258,917 shares of Common Stock.

The filing also shows an indirect holding of 233,924 shares of Common Stock held by a trust. According to a footnote, the sale was executed under a pre-arranged Rule 10b5-1 trading plan adopted on September 4, 2025, indicating it was scheduled in advance.

Insider Trade Summary 10b5-1

Net Seller: 6,515 shares ($612,605)

Net Sell 2 txns

Insider Lewis William

Role Chair and CEO

Sold 6,515 shs ($613K)

Type	Security	Shares	Price	Value
Sale	Common Stock	6,515	$94.03	$613K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 258,917 shares (Direct, null); Common Stock — 233,924 shares (Indirect, By trust)

Footnotes (1)

[object Object]

Key Figures

Shares sold: 6,515 shares Sale price: $94.03 per share Direct holdings after sale: 258,917 shares +2 more

5 metrics

Shares sold 6,515 shares Open-market sale of Common Stock

Sale price $94.03 per share Price for the 6,515 sold shares

Direct holdings after sale 258,917 shares Direct Common Stock owned following transaction

Indirect holdings by trust 233,924 shares Common Stock held indirectly by trust

10b5-1 plan adoption date September 4, 2025 Date plan governing the sale was adopted

Key Terms

Rule 10b5-1 trading plan, open-market sale, Common Stock, indirect, +1 more

5 terms

Rule 10b5-1 trading plan regulatory

"This transaction was effected pursuant to a 10b5-1 trading plan adopted..."

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.

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.

Common Stock financial

""security_title": "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

indirect financial

""ownership_type": "indirect""

Form 4 regulatory

"INSIDER FILING DATA (Form 4):"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google

Form 4 Insider Transactions: What Each Field Means →

06/10/2026 - 04:05 PM

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^*

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)
06/08/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	06/08/2026		S⁽¹⁾		6,515	D	$94.03	258,917	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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.

Remarks:

	/s/ William Lewis, by Michael A. Smith as Attorney-in-fact	06/10/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did INSMED (INSM) report for William Lewis?

INSMED reported that Chair and CEO William Lewis sold 6,515 shares of Common Stock in an open-market transaction at $94.03 per share. The filing also records his remaining direct and indirect shareholdings after this sale.

How many INSMED (INSM) shares did William Lewis sell and at what price?

William Lewis sold 6,515 shares of INSMED Common Stock at $94.03 per share. This open-market transaction is disclosed in a Form 4 filing and includes updated post-transaction direct and indirect ownership levels.

How many INSMED (INSM) shares does William Lewis hold after the reported sale?

Following the reported sale, William Lewis directly holds 258,917 shares of INSMED Common Stock. The Form 4 also lists 233,924 shares held indirectly by a trust, providing a snapshot of his reported ownership structure.

Was the INSMED (INSM) insider sale by William Lewis part of a 10b5-1 plan?

Yes. A footnote states the transaction was executed under a Rule 10b5-1 trading plan adopted on September 4, 2025. Such plans pre-schedule trades, indicating the timing of this sale was arranged in advance rather than being discretionary.

What type of security was involved in William Lewis’s INSMED (INSM) transaction?

The transaction involved INSMED’s Common Stock. The Form 4 reports an open-market sale of 6,515 common shares at $94.03 per share and discloses Lewis’s updated direct and indirect ownership positions in the same security.

How many INSMED (INSM) shares are held indirectly by William Lewis?

The filing shows an indirect holding of 233,924 INSMED Common Stock shares attributed as held "By trust." This is separate from William Lewis’s directly held 258,917 shares reported after the open-market sale transaction.