William Lewis files Form 144 disclosing share sales

William Lewis filed a Form 144 reporting proposed sales of issuer common stock.

Accepted by SEC EDGAR 03/19/2026 - 04:57 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

William Lewis filed a Form 144 reporting proposed sales of issuer common stock. The filing lists multiple Stock Plan Activity entries with proposed dispositions dated 03/19/2026 and earlier trade dates. Examples shown include proposed sales of 10,699 shares on 03/05/2026 and 10,699 shares on 02/19/2026. The filing lists repeated transactions under the same reporting address and identifies the market as NASDAQ.

Insights

Corporate Governance Specialist

Form 144 by an affiliate lists multiple proposed dispositions; timing and proceeds not stated.

The filing records proposed sales under Stock Plan Activity with individual share counts tied to specific dates, such as 10,699 shares on 03/05/2026 and 10,699 shares on 02/19/2026. This is a regulatory notice of intended resale rather than a company action.

Cash‑flow treatment and aggregate totals are not presented in the excerpt; subsequent exchange reports or Form 4 amendments may show executed trades and resulting holdings.

FAQ

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

What does William Lewis's Form 144 for INSM indicate?

It indicates proposed sales of issuer common stock by William Lewis. The filing lists multiple Stock Plan Activity entries with dated share counts and NASDAQ as the market.

How many shares did William Lewis list on recent dates in the Form 144?

Examples shown include proposed disposals of 10,699 shares on 03/05/2026 and 10,699 shares on 02/19/2026. Several other dated share amounts appear in the filing excerpt.

Does the Form 144 confirm the sales were executed for INSM?

No; Form 144 is a notice of proposed sale and does not by itself confirm execution. The excerpt lists proposed dates and share counts but does not state trade execution or proceeds.

Who receives the proceeds from the transactions listed in the Form 144?

The filing excerpt does not state who receives proceeds. Form 144 typically covers resale by an affiliate; the excerpt does not specify cash‑flow recipients or uses.

Where can I find final details if these proposed sales occurred?

Final executed sales, if any, will typically appear on exchange records or in subsequent insider filings such as Form 4 amendments. Check later SEC filings or exchange transaction reports for confirmation.

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	10699	1535514	215551896	03/19/2026	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	03/19/2026	Stock Plan Activity	Issuer			10699	03/19/2026	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	03/05/2026	10699	1562311
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	02/19/2026	10699	1615250
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	02/09/2026	13396	1979774
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	02/03/2026	3009	470412
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	01/20/2026	10699	1700420
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	01/12/2026	19215	3247325
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

144: Remarks and Signature

Remarks
Date of Notice	03/19/2026
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)