D.E. Shaw discloses 8.3% Gossamer Bio (GOSS) ownership stake

Rhea-AI Filing Summary

D. E. Shaw–affiliated entities report an 8.3% beneficial stake in Gossamer Bio, Inc. common stock. The group may be deemed to beneficially own 40,630,726 Common Shares out of 488,846,722 shares outstanding as of June 5, 2026.

Valence holds 38,362,468 shares, or about 7.8% of the class. Cogence holds 1,878,827 shares, or about 0.4%, and funds under DESIM management hold 389,431 shares, or about 0.1%, including 1,200 shares in DSIF. Various D. E. Shaw entities have shared voting and dispositive power, while none owns shares directly and David E. Shaw disclaims beneficial ownership.

Key Figures

Total beneficial ownership: 40,630,726 Common Shares Shares outstanding: 488,846,722 Common Shares Valence holding: 38,362,468 Common Shares +5 more

8 metrics

Total beneficial ownership 40,630,726 Common Shares Beneficially owned by D. E. Shaw–affiliated entities; 8.3% of class

Shares outstanding 488,846,722 Common Shares Issued and outstanding as of June 5, 2026

Valence holding 38,362,468 Common Shares Beneficially owned by Valence; about 7.8% of class

Cogence holding 1,878,827 Common Shares Beneficially owned by Cogence; about 0.4% of class

DESIM funds holding 389,431 Common Shares Under DESIM management, including 1,200 DSIF shares; about 0.1% of class

Aggregate percentage 8.3% of outstanding shares Common Shares over which Dr. Shaw may be deemed to share power

Valence percentage 7.8% of outstanding shares Portion of Gossamer Bio owned through Valence

DESCO LLC aggregate power 40,242,495 Common Shares Shares over which DESCO LLC may share voting and dispositive power

Key Terms

beneficially owned, shared power to vote or direct the vote, Schedule 13D, Transaction Support Agreement, +2 more

6 terms

beneficially owned financial

"The 38,362,468 Common Shares beneficially owned by Valence (the "Valence Shares") represent approximately 7.8% of the outstanding Common Shares."

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.

shared power to vote or direct the vote financial

"DESCO LP ... may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of, 40,630,726 Common Shares."

Schedule 13D regulatory

"Item 5(a) of the Initial is hereby amended and restated as follows:"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

Transaction Support Agreement financial

"Exhibit 99.5 - Transaction Support Agreement with the Issuer, dated May 18, 2026, incorporated by reference..."

A transaction support agreement is a contract among the parties involved in a pending deal that spells out who must do what, who bears which risks, and how any problems discovered before or after closing will be handled. Think of it as a moving checklist and shared rulebook that helps the deal finish smoothly. Investors care because its terms affect the likelihood and timing of closing, potential costs or liabilities after the deal, and the value or dilution of their holdings.

Senior Secured First Lien Convertible Notes due 2030 financial

"Exhibit 99.7 - Indenture governing Senior Secured First Lien Convertible Notes due 2030, incorporated by reference..."

Purchase Warrant Agreement financial

"Exhibit 99.8 - Purchase Warrant Agreement, dated June 4, 2026, incorporated by reference herein..."

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Available on EDGAR 07/01/2026 - 09:24 PM Accepted by SEC EDGAR 07/01/2026 - 09:23 PM Learn about SEC filing dates

FAQ

What stake in Gossamer Bio (GOSS) do D. E. Shaw entities report?

D. E. Shaw–related entities report beneficial ownership of 40,630,726 Gossamer Bio Common Shares, representing about 8.3% of the outstanding stock. This ownership is held through Valence, Cogence, and funds managed by DESIM rather than directly by the parent entities.

How many Gossamer Bio (GOSS) shares are outstanding in this filing?

The filing cites 488,846,722 Gossamer Bio Common Shares issued and outstanding as of June 5, 2026. This figure comes from the company’s definitive proxy statement filed on June 9, 2026 and serves as the basis for the reported ownership percentages.

Which D. E. Shaw entities hold Gossamer Bio (GOSS) shares and in what amounts?

Valence holds 38,362,468 shares (about 7.8%), Cogence holds 1,878,827 shares (about 0.4%), and funds under DESIM management hold 389,431 shares (about 0.1%). These holdings together underpin the reported aggregate 40,630,726-share beneficial position.

Does David E. Shaw personally own Gossamer Bio (GOSS) shares according to this filing?

The filing states that David E. Shaw does not own Gossamer Bio Common Shares directly and disclaims beneficial ownership. He may be deemed to share voting and dispositive power over 40,630,726 shares only through his control of various D. E. Shaw management entities.

What percentage of Gossamer Bio (GOSS) does Valence alone beneficially own?

Valence beneficially owns 38,362,468 Gossamer Bio Common Shares, representing approximately 7.8% of the outstanding stock. Valence has power to vote and dispose of these shares, separate from the additional holdings managed by Cogence and DESIM.

What key agreements related to Gossamer Bio (GOSS) are referenced in the exhibits?

Referenced exhibits include a Transaction Support Agreement, a Voting Agreement, an Indenture for Senior Secured First Lien Convertible Notes due 2030, and a Purchase Warrant Agreement. These are incorporated by reference from Gossamer Bio’s previously filed Form 8-K reports.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

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)

38341P102

(CUSIP Number)

D. E. Shaw & Co., L.P.
Legal & Compliance, Two Manhattan West, 375 Ninth Ave., 52nd Floor
New York, NY, 10001
212-478-0000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

06/29/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 38341P102

1

Name of reporting person

D. E. Shaw Valence Portfolios, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 38,362,468.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 38,362,468.00

11

Aggregate amount beneficially owned by each reporting person

38,362,468.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.8 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 38341P102

1

Name of reporting person

D. E. Shaw & Co., L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 40,242,495.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 40,242,495.00

11

Aggregate amount beneficially owned by each reporting person

40,242,495.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

8.2 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 38341P102

1

Name of reporting person

D. E. Shaw & Co., L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 40,630,726.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 40,630,726.00

11

Aggregate amount beneficially owned by each reporting person

40,630,726.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

8.3 %

14

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13D

CUSIP Number(s): 38341P102

1

Name of reporting person

David E. Shaw

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 40,630,726.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 40,630,726.00

11

Aggregate amount beneficially owned by each reporting person

40,630,726.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

8.3 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, $0.0001 par value per share
(b)	Name of Issuer: Gossamer Bio, Inc.
(c)	Address of Issuer's Principal Executive Offices: 3115 Merryfield Row, Suite 120, San Diego, CALIFORNIA , 92121.
Item 1 Comment: Introductory Note: This Amendment No. 1 to Schedule 13D ("Amendment No. 1") is filed by and on behalf of each of the Reporting Persons to amend and supplement the Schedule 13D related to the Common Shares of the Issuer previously filed by the Reporting Persons with the Securities and Exchange Commission (the "SEC") on June 11, 2026 (the "Initial Schedule 13D"). Each capitalized term used and not defined herein shall have the meaning assigned to such term in the Initial Schedule 13D. Except as provided herein, each Item of the Initial Schedule 13D remains unchanged.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a) of the Initial Schedule 13D is hereby amended and restated as follows: (a) - (b) Based upon the Issuer's definitive proxy statement, filed with the SEC on June 9, 2026, there were 488,846,722 Common Shares issued and outstanding as of June 5, 2026. Common Shares are beneficially owned by Valence, Cogence, and certain funds under the management of DESIM, including Common Shares in the name of DSIF. Each of Valence, Cogence, DESIM, and DSIF is a Delaware limited liability company and has its business address and principal office at Two Manhattan West, 375 Ninth Avenue, 52nd Floor, New York, NY 10001. The 38,362,468 Common Shares beneficially owned by Valence (the "Valence Shares") represent approximately 7.8% of the outstanding Common Shares. The 1,878,827 Common Shares beneficially owned by Cogence (the "Cogence Shares") represent approximately 0.4% of the outstanding Common Shares. The 389,431 Common Shares under the management of DESIM (the "DESIM Shares"), including the 1,200 Common Shares beneficially owned by DSIF (the "DSIF Shares"), represent approximately 0.1% of the outstanding Common Shares. Valence has the power to vote or direct the vote of (and the power to dispose or direct the disposition of) the Valence Shares. Cogence has the power to vote or direct the vote of (and the power to dispose or direct the disposition of) the Cogence Shares. DESIM has the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the DESIM Shares. DESCO LP, as the investment adviser of Valence, Cogence, and as the managing member of DESIM, which in turn is the investment adviser of DSIF, may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of, 40,630,726 Common Shares. DESCO LLC, as the manager of Valence, Cogence, and DSIF may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of, 40,242,495 Common Shares. As general partner of DESCO LP, DESCO Inc. may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of 40,630,726 Common Shares. As managing member of DESCO LLC, DESCO II, Inc. may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of, 40,242,495 Common Shares. None of DESCO LP, DESCO LLC, DESCO Inc., or DESCO II, Inc., owns any Common Shares directly, and each such entity disclaims beneficial ownership of any Common Shares. Dr. Shaw does not own any Common Shares directly. By virtue of Dr. Shaw's position as President and sole shareholder of DESCO Inc., which is the general partner of DESCO LP, which in turn is the investment adviser of Valence, Cogence, and as the managing member of DESIM, which in turn is the investment adviser of DSIF, and by virtue of Dr. Shaw's position as President and sole shareholder of DESCO II, Inc., which is the managing member of DESCO LLC, which in turn is the manager of Valence, Cogence, and DSIF, Dr. Shaw may be deemed to have the shared power to vote or direct the vote of, and the shared power to dispose or direct the disposition of, the 40,630,726 Common Shares as described above constituting 8.3% of the outstanding Common Shares, and, therefore, Dr. Shaw may be deemed to be the beneficial owner of such Common Shares. David E. Shaw disclaims beneficial ownership of any Common Shares.
(b)	Item 5(b) of the Initial Schedule 13D is hereby amended and supplemented as follows: See Item 5(a) of Amendment No. 1 to the Initial Schedule 13D.
(c)	Item 5(c) of the Initial Schedule 13D is hereby amended and supplemented as follows: Schedule I to Amendment No. 1, which is incorporated by reference into this Item 5(c) as if restated in full herein, describes all of the transactions in Common Shares by the Reporting Persons and/or any affiliates of the Reporting Persons during the past sixty (60) days.
(d)	Item 5(d) of the Initial Schedule 13D is hereby amended and supplemented as follows: To the best of the Reporting Persons' knowledge, no person other than the Reporting Persons or their affiliates has the right to receive or power to direct the receipt of dividends from, or proceeds from the sale of, the 40,630,726 Common Shares, except for such rights and powers as the corresponding investors in Valence, Cogence, and funds under the management of DESIM shall possess.
Item 7.	Material to be Filed as Exhibits.
	Item 7 of the Initial Schedule 13D is hereby amended and restated in its entirety as follows: Exhibit 99.1 - Schedule I (Transactions in the Securities of the Issuer During the Past Sixty Days) Exhibit 99.2 - Power of Attorney, granted by David E. Shaw relating to D. E. Shaw & Co., Inc., in favor of the signatories hereto, among others, dated August 1, 2024. Exhibit 99.3 - Power of Attorney, granted by David E. Shaw relating to D. E. Shaw & Co. II, Inc., in favor of the signatories hereto, among others, dated August 1, 2024. Exhibit 99.4 - Joint Filing Agreement, by and among the Reporting Persons, dated July 1, 2026. Exhibit 99.5 - Transaction Support Agreement with the Issuer, dated May 18, 2026, incorporated by reference to Exhibit 10.1 to the Form 8-K filed by the Issuer on May 18, 2026. (https://www.sec.gov/Archives/edgar/data/1728117/000172811726000036/goss-20260518xexx101xtsa.htm) Exhibit 99.6 - Form of Voting Agreement, dated May 18, 2026, incorporated by reference herein to Exhibit 10.2 to the Form 8-K filed by the issuer on May 18, 2026. (https://www.sec.gov/Archives/edgar/data/1728117/000172811726000036/goss-20260518xexx102xformo.htm) Exhibit 99.7 - Indenture governing Senior Secured First Lien Convertible Notes due 2030, incorporated by reference to Exhibit 10.1 to the Form 8-K filed by the Issuer on June 5, 2026. (https://www.sec.gov/Archives/edgar/data/1728117/000172811726000045/goss-20260604xexx101inde.htm) Exhibit 99.8 - Purchase Warrant Agreement, dated June 4, 2026, incorporated by reference herein to Exhibit 10.3 to the Form 8-K filed by the issuer on June 5, 2026. (https://www.sec.gov/Archives/edgar/data/1728117/000172811726000045/goss-20260604xexx103warr.htm)

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.

D. E. Shaw Valence Portfolios, L.L.C.

Signature:	/s/ Daniel R. Marcus
Name/Title:	Daniel R. Marcus / Authorized Signatory
Date:	07/01/2026

D. E. Shaw & Co., L.L.C.

Signature:	/s/ Daniel R. Marcus
Name/Title:	Daniel R. Marcus / Authorized Signatory
Date:	07/01/2026

D. E. Shaw & Co., L.P.

Signature:	/s/ Daniel R. Marcus
Name/Title:	Daniel R. Marcus / Chief Compliance Officer
Date:	07/01/2026

David E. Shaw

Signature:	/s/ Daniel R. Marcus
Name/Title:	Daniel R. Marcus / Attorney-in-Fact for David E. Shaw
Date:	07/01/2026