INSM Form 144: Proposed sale of common shares

INSM filed a Form 144 disclosing proposed sale of Common Stock.

Rhea-AI Filing Summary

INSM filed a Form 144 disclosing proposed sale of Common Stock. The filing lists recent stock plan activity and shows multiple sales by Michael Smith: 19,638 shares on 03/30/2026, 6,149 shares on 05/22/2026, and 4,109 shares on 05/13/2026. The cover data lists Common stock and an entry dated 06/03/2026.

Insights

Insider Transactions Analyst

Form 144 shows proposed affiliate sale and recent dispositions by a named insider.

The filing records proposed sale activity for Common Stock and lists three dated dispositions by Michael Smith for 19,638, 6,149, and 4,109 shares. These entries are presented as stock plan activity and sales within the provided date range.

Cashflow treatment and aggregate offering mechanics are not stated in the excerpt; subsequent SEC notices or trading reports would show execution details and purchaser types.

Key Figures

Sale on 03/30/2026: 19,638 shares Sale on 05/22/2026: 6,149 shares Sale on 05/13/2026: 4,109 shares +1 more

4 metrics

Sale on 03/30/2026 19,638 shares Sale by Michael Smith

Sale on 05/22/2026 6,149 shares Sale by Michael Smith

Sale on 05/13/2026 4,109 shares Sale by Michael Smith

Cover entry date 06/03/2026 Cover data for Common stock

Key Terms

Form 144, Stock Plan Activity, Securities To Be Sold

3 terms

Form 144 regulatory

"Filer Information | | | 144: Filer Information"

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 | 06/01/2026 | Stock Plan Activity | Issuer"

Securities To Be Sold regulatory

"144: Securities To Be Sold"

FAQ

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

What does INSM's Form 144 disclose?

It discloses a proposed sale of Common Stock and recent insider sales. The filing lists 19,638, 6,149, and 4,109 shares sold by Michael Smith on the stated dates, and a cover entry dated 06/03/2026.

Who is listed as selling shares in the INSM Form 144?

The filing names Michael Smith as the seller. The record shows sales dated 03/30/2026 (19,638 shares), 05/22/2026 (6,149 shares), and 05/13/2026 (4,109 shares) as provided in the excerpt.

Are the sale dates and share counts specified in the filing?

Yes; the excerpt lists explicit dates and share counts. The entries show 03/30/2026 — 19,638 shares, 05/22/2026 — 6,149 shares, and 05/13/2026 — 4,109 shares attributed to Michael Smith.

Does the excerpt state who receives proceeds or the sale method?

The excerpt does not state proceeds recipients or sale methods. It labels the activity as Stock Plan Activity and lists dates and amounts; additional filings would be needed for proceeds or distribution method details.

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

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Accepted by SEC EDGAR 06/03/2026 - 04:21 PM EDT 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	0001870278
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	Michael Smith
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	2159	220800	216752451	06/03/2026	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	06/01/2026	Stock Plan Activity	Issuer			2159	06/01/2026	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
Michael Smith 700 US Highway 202/206 Bridgewater NJ 08807	Common	05/22/2026	6149	666951
Michael Smith 700 US Highway 202/206 Bridgewater NJ 08807	Common	05/13/2026	4109	477373
Michael Smith 700 US Highway 202/206 Bridgewater NJ 08807	Common	03/30/2026	19638	2964929

144: Remarks and Signature

Remarks
Date of Notice	06/03/2026
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	Michael Smith
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)