683 Capital reports 3.90% stake in Gossamer Bio

Gossamer Bio, Inc. ownership disclosure: 683 Capital Partners, LP beneficially owned 5,000,000 shares of Common Stock and warrants exercisable for 4,331,304 shares.

Accepted by SEC EDGAR 03/24/2026 - 04:48 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Gossamer Bio, Inc. ownership disclosure: 683 Capital Partners, LP beneficially owned 5,000,000 shares of Common Stock and warrants exercisable for 4,331,304 shares. The reporting group may be deemed to beneficially own these amounts through 683 Capital Management, LLC and Ari Zweiman. The filing states this position represents approximately 3.90% of the company on an as‑adjusted basis, using 234,696,281 shares outstanding as of March 10, 2026 and including the currently exercisable warrants. The Reporting Persons report shared voting and dispositive power over the listed securities.

Insights

Institutional Ownership Analyst

Large hedge fund reports a sub‑5% position including exercisable warrants.

The filing discloses that 683 Capital Partners, LP holds 5,000,000 shares plus warrants for 4,331,304 shares, which the schedule treats as currently exercisable when computing beneficial ownership. The issuer share base used is 234,696,281 shares as of March 10, 2026.

Shared voting and dispositive power is reported via the manager and managing member structure. Subsequent trading or exercises by the holders will determine any near‑term change in public float; timing and cash‑flow treatment are not disclosed in this excerpt.

Corporate Governance Specialist

Filing reflects standard Section 13 reporting of beneficial ownership via investment vehicle.

The schedule attributes beneficial ownership to the partnership and to affiliated manager and manager's principal, consistent with group attribution rules. It states the warrants are "currently exercisable" and therefore counted in the 3.90% calculation.

Investors may note the filing classifies power as shared rather than sole; filings describing any changes in voting or disposition authority would appear in subsequent amendments or other Section 13 filings.

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

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Gossamer Bio, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

(CUSIP Number)

03/18/2026

(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 No.

1

Names of Reporting Persons

683 Capital Management, LLC

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 9,331,304.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 9,331,304.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,331,304.00

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)

3.9 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP No.

1

Names of Reporting Persons

683 Capital Partners, LP

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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 9,331,304.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 9,331,304.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,331,304.00

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)

3.9 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No.

1

Names of Reporting Persons

Ari Zweiman

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 STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 9,331,304.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 9,331,304.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,331,304.00

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)

3.9 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Gossamer Bio, Inc.
(b)	Address of issuer's principal executive offices: 3115 MERRYFIELD ROW, SUITE 120, SAN DIEGO, CALIFORNIA 92121
Item 2.
(a)	Name of person filing: 683 Capital Management, LLC 683 Capital Partners, LP Ari Zweiman
(b)	Address or principal business office or, if none, residence: The principal business address for each of the Reporting Persons is 1700 Broadway, Suite 4200, New York, New York 10019.
(c)	Citizenship: 683 Capital Management, LLC - DELAWARE 683 Capital Partners, LP - DELAWARE Ari Zweiman - UNITED STATES
(d)	Title of class of securities: Common Stock, $0.0001 par value per share
(e)	CUSIP No.:
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: As of March 24, 2026, 683 Capital Partners, LP beneficially owned 5,000,000 shares of Common Stock and warrants to purchase 4,331,304 shares of Common Stock which are currently exercisable. 683 Capital Management, LLC, as the investment manager of 683 Capital Partners, LP, may be deemed to have beneficially owned the 5,000,000 shares of Common Stock and warrants to purchase 4,331,304 shares of Common Stock beneficially owned by 683 Capital Partners, LP. Ari Zweiman, as the Managing Member of 683 Capital Management, LLC, may be deemed to have beneficially owned the 5,000,000 shares of Common Stock and warrants to purchase 4,331,304 shares of Common Stock beneficially owned by 683 Capital Management, LLC. The following percentage is based on 234,696,281 shares of common stock ($0.0001 par value) outstanding as of March 10, 2026, as disclosed in the Issuer's Form 10-K filed on March 17, 2026, plus 4,331,304 shares of Common Stock issuable upon exercise of currently exercisable warrants held by the Reporting Persons. As of March 24, 2026, the Reporting Persons may be deemed to have beneficially owned approximately 3.90% of the outstanding Common Shares.
(b)	Percent of class: 3.90 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Cover Pages Items 5-9.
	(ii) Shared power to vote or to direct the vote: See Cover Pages Items 5-9.
	(iii) Sole power to dispose or to direct the disposition of: See Cover Pages Items 5-9.
	(iv) Shared power to dispose or to direct the disposition of: See Cover Pages Items 5-9.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
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.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. See Exhibit A to Schedule 13G filed on March 2, 2026.
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.

683 Capital Management, LLC

Signature:	Ari Zweiman
Name/Title:	Managing Member
Date:	03/24/2026

683 Capital Partners, LP

Signature:	Ari Zweiman
Name/Title:	Authorized Person
Date:	03/24/2026

Ari Zweiman

Signature:	Ari Zweiman
Name/Title:	Self
Date:	03/24/2026