INSM affiliate files Form 144 reporting share sales

INSM filed a Form 144 reporting proposed sales of Common Stock by an affiliate.

Rhea-AI Filing Summary

INSM filed a Form 144 reporting proposed sales of Common Stock by an affiliate. The filing lists multiple proposed dispositions by William Lewis, including sales on 04/16/2026, 05/04/2026, 05/13/2026, 05/18/2026, 06/03/2026, 06/08/2026, and 06/25/2026, with individual share quantities shown for each date.

Insights

Corporate Governance Analyst

Form 144 lists multiple affiliate share dispositions by William Lewis.

The filing enumerates specific proposed sales of Common Stock by William Lewis on seven dates in 2026 with per‑date share quantities. This is a regulatory notice of proposed sales, not a confirmation of completed trades.

Timing and cash‑flow treatment are not stated in the excerpt; subsequent transaction confirmations would appear in trade reports or Forms 4/5.

Key Figures

Form type: Form 144 Sale on 04/16/2026: 10,699 shares Sale on 05/04/2026: 10,699 shares +5 more

8 metrics

Form type Form 144 Notice of proposed sale by affiliate

Sale on 04/16/2026 10,699 shares Listed proposed sale by William Lewis

Sale on 05/04/2026 10,699 shares Listed proposed sale by William Lewis

Sale on 05/13/2026 13,283 shares Listed proposed sale by William Lewis

Sale on 05/18/2026 25,564 shares Listed proposed sale by William Lewis

Sale on 06/03/2026 7,605 shares Listed proposed sale by William Lewis

Sale on 06/08/2026 6,515 shares Listed proposed sale by William Lewis

Sale on 06/25/2026 21,398 shares Listed proposed sale by William Lewis

Key Terms

Form 144, Stock Plan Activity, Issuer

3 terms

Form 144 regulatory

"144: Securities To Be Sold"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Stock Plan Activity financial

"Common | 07/09/2026 | Stock Plan Activity"

Issuer regulatory

"Stock Plan Activity | Issuer"

FAQ

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

What does INSM's Form 144 disclose about William Lewis?

The filing discloses proposed sales of Common Stock by William Lewis on seven dates in 2026, with specific share counts for each date. It lists sale dates and share quantities but does not confirm settlement or proceeds.

Which dates and share amounts are shown in the INSM Form 144?

The excerpt lists sales dated 04/16/2026 (10,699), 05/04/2026 (10,699), 05/13/2026 (13,283), 05/18/2026 (25,564), 06/03/2026 (7,605), 06/08/2026 (6,515), and 06/25/2026 (21,398).

Does the Form 144 confirm completed sales or proceeds received?

No. Form 144 provides notice of proposed sales by an affiliate; it does not confirm that sales settled or state cash proceeds. Settlement and proceeds would be reported elsewhere if and when transactions complete.

Will these Form 144 entries appear on Forms 4 or 5?

If the transactions are executed, corresponding Forms 4 or 5 may report completed trades and resulting holdings. The Form 144 itself is a pre‑sale notice and does not replace post‑trade insider reporting.

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

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Accepted by SEC EDGAR 07/09/2026 - 04:29 PM Learn about SEC filing dates

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	1256029	216752451	07/09/2026	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	07/09/2026	Stock Plan Activity	Issuer			10699	07/09/2026	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	06/25/2026	21398	2210653
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	06/08/2026	6515	612576
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	06/03/2026	7605	777746
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	05/18/2026	25564	2718106
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	05/13/2026	13283	1543186
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	05/04/2026	10699	1469434
William Lewis 700 US Highway 202/206 Bridgewater NJ 08807	Common	04/16/2026	10699	1540292

144: Remarks and Signature

Remarks
Date of Notice	07/09/2026
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)