INSMED Inc ownership update: a Schedule 13G/A amendment reports that certain related reporting persons together hold sizable positions in Common Stock. Darwin Global Management, Ltd. and related parties report 16,805,184 shares (representing 7.8%) and Darwin Global Master Fund, Ltd. reports 14,182,375 shares (representing 6.6%), using an outstanding share base of 215,852,149 shares as of March 6, 2026. The filing attributes shared voting and dispositive power and is signed by authorized representatives.
Positive
None.
Negative
None.
Insights
Concentrated institutional stake noted; holdings reflect shared control structures.
The filing lists 16,805,184 shares for Darwin Global and affiliated reporting persons and 14,182,375 shares for the Master Fund, tied to a 215,852,149 share outstanding base as of March 6, 2026. The report shows shared voting and shared dispositive power rather than sole control.
Actual market activity and cash flow treatment are not included in the excerpt; subsequent filings or public disclosures would show sale/acquisition behavior if it occurs.
Stake structure implies coordinated influence without sole voting authority.
The statement clarifies that Reporting Persons include an investment manager, its Chief Investment Officer, and a Master Fund. The filing emphasizes shared powers (voting and dispositive) for the reported shares, which can reflect pooled investment arrangements or nominee holdings.
Signatures by authorized officers are included; legal qualifiers note the filing is not an admission of beneficial ownership under Section 13.
Key Figures
Outstanding shares:215,852,149 sharesDarwin Global holdings:16,805,184 sharesDarwin Global Master Fund holdings:14,182,375 shares
3 metrics
Outstanding shares215,852,149 sharesas of March 6, 2026
Darwin Global holdings16,805,184 sharesreported beneficially owned (7.8%)
Darwin Global Master Fund holdings14,182,375 sharesreported beneficially owned (6.6%)
Key Terms
Schedule 13G/A, Beneficially owned, Shared dispositive power
3 terms
Schedule 13G/Aregulatory
"Item 1. Name of issuer: INSMED Inc and the filing title"
A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.
Beneficially ownedfinancial
"Item 4. Ownership (a) Amount beneficially owned: The information required by Item 4(a)"
Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.
What stake does Darwin Global report in INSM (INSMED Inc)?
Darwin Global and related reporting persons report 16,805,184 shares, representing 7.8% of INSM's Common Stock based on 215,852,149 shares outstanding as of March 6, 2026. The filings show shared voting and dispositive power.
How many shares does Darwin Global Master Fund hold in INSM?
Darwin Global Master Fund, Ltd. reports beneficial ownership of 14,182,375 shares, representing 6.6% of Common Stock using the same outstanding share base of 215,852,149 as of March 6, 2026 cited in the filing.
Does the Schedule 13G/A show sole voting control by the reporting persons?
No. The filing indicates 0 sole voting power and reports shared voting and shared dispositive power for the listed share amounts, signaling collective or managed ownership rather than individual sole control.
Who signed the amended Schedule 13G/A for these holdings?
The amendment is signed by John Legge as Director and Chief Financial Officer and by Dr. Abhishek Trehan individually, with John Legge also signing on behalf of Darwin Global Management, Ltd., dated May 15, 2026.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 4)
INSMED Inc
(Name of Issuer)
Common Stock, par value $0.01 per share
(Title of Class of Securities)
457669307
(CUSIP Number)
03/31/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
457669307
1
Names of Reporting Persons
Darwin Global Management, Ltd.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
JERSEY
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
16,805,184.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
16,805,184.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
16,805,184.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
7.8 %
12
Type of Reporting Person (See Instructions)
IA, OO
SCHEDULE 13G
CUSIP Number(s):
457669307
1
Names of Reporting Persons
Dr. Abhishek Trehan
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED KINGDOM
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
16,805,184.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
16,805,184.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
16,805,184.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
7.8 %
12
Type of Reporting Person (See Instructions)
IN
SCHEDULE 13G
CUSIP Number(s):
457669307
1
Names of Reporting Persons
Darwin Global Master Fund, Ltd.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
14,182,375.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
14,182,375.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
14,182,375.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
6.6 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
INSMED Inc
(b)
Address of issuer's principal executive offices:
700 US HIGHWAY 202/206, BRIDGEWATER NJ 08807
Item 2.
(a)
Name of person filing:
This statement is filed by:
(i) Darwin Global Management, Ltd., a limited company incorporated under the laws of Jersey ("Darwin Global") with respect to the shares of common stock, par value $0.01 per share ("Common Stock") of Insmed Incorporated (the "Company") directly held by (a) Master Fund (as defined below), to which Darwin Global serves as investment manager and (b) segregated accounts (the "Segregated Accounts") for which Darwin Global serves as an appointed sub-investment advisor;
(ii) Dr. Abhishek Trehan ("Dr. Trehan"), the Chief Investment Officer and the controlling person of Darwin Global, with respect to the shares of Common Stock directly held by each of Master Fund and the Segregated Accounts; and
(iii) Darwin Global Master Fund Ltd. ("Master Fund"), a Cayman Islands exempted company, with respect to the shares of Common Stock directly held by it.
The foregoing persons are hereinafter sometimes each referred to as a "Reporting Person" and collectively referred to as the "Reporting Persons."
The filing of this statement should not be construed as an admission that any Reporting Person is, for purposes of Section 13 of the Securities Exchange Act of 1934, the beneficial owner of the securities reported herein.
(b)
Address or principal business office or, if none, residence:
The address of the business office of each of the Reporting Persons is Whiteley Chambers, Don Street, St. Helier, Jersey JE2 4TR.
(c)
Citizenship:
Darwin Global is a Jersey limited company. Dr. Trehan is a British citizen. Master Fund is a Cayman Islands exempted company.
(d)
Title of class of securities:
Common Stock, par value $0.01 per share
(e)
CUSIP No.:
457669307
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 215,852,149 shares of Common Stock outstanding as of March 6, 2026, as reported in the Company's Definitive Proxy Statement on Schedule 14A, filed with the Securities and Exchange Commission on April 1, 2026.
(b)
Percent of class:
7.8%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
See Item 2(a).
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
Darwin Global Management, Ltd.
Signature:
/s/ John Legge
Name/Title:
John Legge, Director and Chief Financial Officer
Date:
05/15/2026
Dr. Abhishek Trehan
Signature:
/s/ Dr. Abhishek Trehan
Name/Title:
Dr. Abhishek Trehan, individually
Date:
05/15/2026
Darwin Global Master Fund, Ltd.
Signature:
/s/ John Legge
Name/Title:
By: Darwin Global Management, Ltd, its Investment Manager, By: John Legge, Director and Chief Financial Officer
