INSM insider files Form 144 for proposed share sales

INSM submitted a Form 144 notice reporting proposed sales of Common Stock by an insider.

Rhea-AI Filing Summary

INSM submitted a Form 144 notice reporting proposed sales of Common Stock by an insider. The filing lists prior sales during the past three months by Michael Smith: 19,638 shares on 03/30/2026 and 24,774 shares on 02/24/2026. The filing references Stock Plan Activity and shows post-transaction holdings of 2,964,929 and 3,859,153 shares respectively.

Insights

Corporate Governance Analyst

Routine disclosure of insider stock sales; no new capital or material corporate action.

The filing is a regulatory notice of proposed resale under a stock plan and lists past sales by Michael Smith of 19,638 and 24,774 shares on 03/30/2026 and 02/24/2026. These are reported sales rather than company issuances.

Timing and cash‑flow treatment are not specified in the excerpt; subsequent filings or broker reports would show execution details if relevant.

Key Figures

Sale on 03/30/2026: 19,638 shares Sale on 02/24/2026: 24,774 shares Post-transaction holdings (example 1): 2,964,929 shares +1 more

4 metrics

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

Sale on 02/24/2026 24,774 shares sale reported by Michael Smith

Post-transaction holdings (example 1) 2,964,929 shares holdings shown alongside 03/30/2026 sale

Post-transaction holdings (example 2) 3,859,153 shares holdings shown alongside 02/24/2026 sale

Key Terms

Form 144, Stock Plan Activity, Issuer

3 terms

Form 144 regulatory

"Form 144 notice reporting proposed sale of securities"

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

"Stock Plan Activity listed as the reason for securities to be sold"

Issuer regulatory

"Issuer identified for the securities to be sold"

FAQ

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

What does INSM's Form 144 filing mean?

It notifies the SEC of a proposed resale of shares by an insider. The filing lists proposed or previously executed sales and identifies the insider and share counts for regulatory transparency.

How many shares did Michael Smith report selling for INSM?

The filing lists two sales in the past three months: 19,638 shares on 03/30/2026 and 24,774 shares on 02/24/2026. These figures are the amounts reported in the notice.

Do Form 144 notices affect INSM's cash or proceeds to the company?

Form 144 reports insider resale activity; it does not indicate proceeds to the issuer. The filing here reflects insider sales under a stock plan; it does not state company receipt of cash.

Where can I find execution details for the reported sales?

Execution timing and proceeds are typically shown in broker confirmations or secondary market filings. The Form 144 lists intended or reported sales; confirm execution in transaction reports or subsequent SEC filings.

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

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Accepted by SEC EDGAR 05/13/2026 - 05:18 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	4109	477383	216752451	05/13/2026	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	05/11/2026	Stock Plan Activity	Issuer			4109	05/11/2026	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	03/30/2026	19638	2964929
Michael Smith 700 US Highway 202/206 Bridgewater NJ 08807	Common	02/24/2026	24774	3859153

144: Remarks and Signature

Remarks
Date of Notice	05/13/2026
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)