GOSS Form 4: 125,000 PSU grant vests on NDA approval or change-in-control

Rhea-AI Filing Summary

Christian Waage, Executive Vice President, Tech Ops and Admin at Gossamer Bio, Inc. (GOSS), received a performance stock unit award of 125,000 shares on 10/01/2025. The award has a $0 purchase price and will vest in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, in either case on or before the fourth anniversary of the grant, subject to continuous service. Following the grant, Mr. Waage is reported to beneficially own 710,934 shares directly, plus 45,892 shares held by a family trust and 22,222 held in a trust for his son. The Form 4 was signed by an attorney-in-fact on 10/02/2025.

Positive

• 125,000 performance stock units tie compensation to seralutinib NDA approval or change-in-control, aligning incentives
• Vesting capped at four years, providing a clear timeframe for the performance condition
• Reporting shows 710,934 shares directly owned, increasing transparency of insider holdings

Negative

• None.

Insights

Corporate Governance Expert

Award ties executive pay to a regulatory milestone and change-in-control within four years.

The 125,000 performance stock unit award vests only upon the earlier of NDA approval for seralutinib or a change in control, and is limited to the fourth anniversary of the grant. This structure links compensation to a specific corporate outcome rather than time-based vesting.

The award was granted at a $0 price and increases the reporting person’s direct beneficial ownership to 710,934 shares while also noting 45,892 and 22,222 shares held indirectly. The instrument is contingent on continued service, which retains retention leverage for the company.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Christian Waage

(Last) (First) (Middle)

3115 MERRYFIELD ROW, SUITE 120

(Street)

SAN DIEGO CA 92121

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Gossamer Bio, Inc. [ GOSS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, Tech Ops and Admin

3. Date of Earliest Transaction (Month/Day/Year)
10/01/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/01/2025		A		125,000(1)	A	$0	710,934	D
Common Stock								45,892	I	By family trust
Common Stock								22,222	I	By trust FBO son

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents performance stock unit award, which will vest in full upon the earlier of (i) the approval of a new drug application for seralutinib or (ii) a change in control, in either case on or prior to the fourth anniversary of the grant date, and subject to the Reporting Person's continuous service to the Issuer.

Remarks:

	/s/ Jeff Boerneke, Attorney-in-Fact	10/02/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Christian Waage report on Form 4 for GOSS?

He reported a grant of 125,000 performance stock units on 10/01/2025 that vest upon NDA approval for seralutinib or a change in control, and updated his beneficial ownership to 710,934 shares.

What are the vesting conditions for the 125,000 units?

The units vest in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, in either case on or before the fourth anniversary of the grant, subject to continuous service.

Was there any cash paid for the award reported on GOSS Form 4?

No cash payment was reported; the transaction price is shown as $0.

Does the filing show indirect holdings for the reporting person?

Yes. The filing lists 45,892 shares held by a family trust and 22,222 shares in a trust for the reporting person’s son.

When was the Form 4 signed and filed?

The Form 4 was executed by an attorney-in-fact and signed on 10/02/2025.