INSM Rule 144 Notice: 25,000 Shares Proposed Sale, $3.19M Value

Rhea-AI Filing Summary

Insmed, Inc. (INSM) Form 144 notifies market participants that an insider intends to sell 25,000 shares of common stock through Merrill Lynch on 08/19/2025, with an aggregate market value of $3,188,795.00. The filing shows total outstanding shares of 211,374,786, indicating the proposed sale is a small fraction of the float. The shares to be sold were principally acquired through the company's stock plan between 2020 and 2025, with specific grant lots listed. The filer also reported two recent open-market sales in June 2025 totaling 12,546 shares for gross proceeds of $1,188,677.00. The notice contains the standard attestation that the seller is not aware of undisclosed material adverse information.

Positive

• Full Rule 144 disclosure provided with broker, sale date, and aggregate value
• Securities sourced from company stock plan awards (dates 2020–2025), indicating routine vesting
• Seller attests they are not aware of undisclosed material adverse information

Negative

• Insider is selling shares (25,000 planned plus 12,546 sold in June 2025), reflecting ongoing dilution of insider holdings

Insights

Securities Analyst

TL;DR: Insider intends to sell 25,000 shares (small relative to outstanding shares); recent June sales totaled 12,546 shares.

The proposed 25,000-share sale via Merrill Lynch at an aggregate value of $3.19 million is disclosed under Rule 144 and appears to be sourced from routine stock plan activity spanning 2020–2025. Relative to the issuer's reported outstanding shares (211.37 million), the planned sale represents roughly 0.012% of shares outstanding, which is immaterial from a supply-demand perspective. The two prior sales in June 2025 (10,686 and 1,860 shares) generated $1.19 million, showing the filer has been executing partial disposals over the past month. There is no earnings or operational information in this form to assess company fundamentals.

Corporate Governance Expert

TL;DR: Filing reflects compliant disclosure of insider sales derived from stock plan awards; no governance red flags visible.

The Form 144 provides required disclosure of the source of shares (stock plan grants) and recent sale activity, and includes the seller's attestation about possession of material non-public information. The schedule of multiple grant dates and small lot sizes suggests routine vesting and planned diversification rather than emergency or undisclosed issues. Absent other disclosures, this filing alone does not signal governance concerns but does document insider liquidity events that investors may note for ownership trends.

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

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

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

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	25000	3188795.00	211374786	08/19/2025	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	05/15/2020	Stock Plan Activity	Issuer			1778	05/15/2020	n/a
Common	01/03/2021	Stock Plan Activity	Issuer			4304	01/03/2021	n/a
Common	01/04/2021	Stock Plan Activity	Issuer			2675	01/04/2021	n/a
Common	05/15/2021	Stock Plan Activity	Issuer			2913	05/15/2021	n/a
Common	01/03/2022	Stock Plan Activity	Issuer			5650	01/03/2022	n/a
Common	01/04/2022	Stock Plan Activity	Issuer			929	01/04/2022	n/a
Common	01/05/2022	Stock Plan Activity	Issuer			608	01/05/2022	n/a
Common	05/11/2024	Stock Plan Activity	Issuer			2999	05/11/2024	n/a
Common	05/12/2024	Stock Plan Activity	Issuer			1522	05/12/2024	n/a
Common	01/04/2025	Stock Plan Activity	Issuer			1622	01/04/2025	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
Roger Adsett 700 US Highway 202/206 Bridgewater NJ 08807	Common	06/16/2025	10686	1055687.00
Roger Adsett 700 US Highway 202/206 Bridgewater NJ 08807	Common	06/03/2025	1860	132990.00

144: Remarks and Signature

Remarks

Date of Notice

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

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does the Form 144 filed for INSM report?

The form reports a proposed sale of 25,000 common shares via Merrill Lynch on 08/19/2025 with aggregate market value $3,188,795 and lists recent sales in June 2025 totaling 12,546 shares.

How were the shares being sold by the INSM filer acquired?

The shares were acquired through the issuer's stock plan between 05/15/2020 and 01/04/2025, with specific grant lots and amounts listed.

How large is the proposed sale relative to Insmed’s outstanding shares?

The proposed 25,000-share sale represents about 0.012% of the reported 211,374,786 shares outstanding.

Who is the broker handling the proposed sale?

The broker named is Merrill Lynch, 1800 K ST NW Suite 800 Washington DC 20006.

Did the filer sell any INSM shares recently?

Yes: sales on 06/03/2025 (1,860 shares, $132,990) and 06/16/2025 (10,686 shares, $1,055,687) are reported.