INSM holder plans sale of 19,215 common shares

Insmed shareholder William Lewis has filed a notice of proposed stock sales under Rule 144.

Accepted by SEC EDGAR 01/12/2026 - 04:58 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Insmed shareholder William Lewis has filed a notice of proposed stock sales under Rule 144. The filing covers the planned sale of 19,215 shares of Insmed common stock through Merrill Lynch on the NASDAQ around 01/12/2026, with an aggregate market value of 3,247,325. The company reports 213,273,469 shares of common stock outstanding. The shares to be sold were acquired through stock plan activity from the issuer on several dates in January 2026, including 10,699 shares on 01/12/2026. Over the prior three months, William Lewis sold additional Insmed common shares, including 10,699 shares on both 12/04/2025 and 12/18/2025, and smaller blocks in January 2026, with disclosed gross proceeds for each transaction.

FAQ

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

How many Insmed (INSM) shares does William Lewis plan to sell under this Form 144?

The notice lists a planned sale of 19,215 shares of Insmed common stock, to be sold through Merrill Lynch on the NASDAQ around 01/12/2026, with an aggregate market value of 3,247,325.

How many Insmed (INSM) shares are outstanding according to this Form 144?

The filing states that 213,273,469 shares of Insmed common stock were outstanding at the time referenced in the notice.

How did William Lewis acquire the Insmed (INSM) shares being sold?

The shares to be sold were acquired through Stock Plan Activity from the issuer on multiple dates, including 10,699 shares on 01/12/2026, 2,926 shares on 01/06/2026, 2,113 shares on 01/05/2026, and 3,477 shares on 01/04/2026.

What Insmed (INSM) stock sales has William Lewis made in the past three months?

Over the past three months, William Lewis sold Insmed common stock in several transactions, including 10,699 shares on 12/04/2025 for gross proceeds of 2,199,583, 10,699 shares on 12/18/2025 for 1,786,437, and additional sales of 4,096 shares on 01/06/2026 for 709,959, 2,357 shares on 01/07/2026 for 412,639, and 3,223 shares on 01/08/2026 for 561,349.

Which broker is handling the planned Insmed (INSM) share sale for William Lewis?

The planned sale of Insmed common stock is listed as being executed through Merrill Lynch, located at 1800 K ST NW, Suite 800, Washington, DC 20006.

What does the Form 144 representation say about non-public information for Insmed (INSM)?

By signing the notice, the selling person represents that they do not know any material adverse information about Insmed’s current or prospective operations that has not been publicly disclosed.

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

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Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001402051
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	INSMED INC
SEC File Number	000-30739
Address of Issuer	700 US Highway 202/206 Bridgewater NEW JERSEY 08807
Phone	9089779900
Name of Person for Whose Account the Securities are To Be Sold	William Lewis
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Merrill Lynch 1800 K ST NW Suite 800 Washington DC 20006	19215	3247325	213273469	01/12/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	01/12/2026	Stock Plan Activity	Issuer			10699	01/12/2026	n/a
Common	01/06/2026	Stock Plan Activity	Issuer			2926	01/06/2026	n/a
Common	01/05/2026	Stock Plan Activity	Issuer			2113	01/05/2026	n/a
Common	01/04/2026	Stock Plan Activity	Issuer			3477	01/04/2026	n/a

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	01/08/2026	3223	561349
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	01/07/2026	2357	412639
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	01/06/2026	4096	709959
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	12/18/2025	10699	1786437
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	12/04/2025	10699	2199583

144: Remarks and Signature

Remarks
Date of Notice	01/12/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	09/04/2025
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	William Lewis
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)