[Form 4] Gossamer Bio, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Form 4 overview: On 06/26/2025, Gossamer Bio, Inc. (GOSS) filed a Form 4 disclosing a routine equity award to outside director Sandra Milligan.

• Type of security: Non-qualified stock option covering 115,000 common shares.
• Grant date: 06/25/2025  |  Exercise price: $1.36 per share.
• Vesting: 100 % on the earlier of (a) the first anniversary of the grant or (b) the next annual shareholder meeting, contingent on continued board service.
• Expiration: 06/24/2035 (10-year life).
• Ownership impact: Following the grant, Milligan beneficially owns 115,000 derivative securities; no common shares were bought or sold.

The grant was made under the company’s Non-Employee Director Compensation Program and reported under a standard transaction code “A” (grant without cash payment). Because this is a routine compensation award with no accompanying sale of shares or material change in ownership concentration, the filing is administrative and low-impact for investors.

Insights

Corporate Governance Expert

TL;DR: Routine director option grant; no red flags, minimal dilution, governance-aligned with typical small-cap practice.

The company is compensating outside director Sandra Milligan with 115 k options at $1.36, aligning her incentives with shareholders. Vesting is time-based and expires in 10 years, consistent with peer norms. The award represents roughly 0.1 % of outstanding shares (assuming ~110 m shares O/S), an immaterial potential dilution. No accelerated vesting or repricing clauses are disclosed. Overall, the filing supports standard governance practice and does not alter the investment thesis.

Securities Analyst

TL;DR: Minor option grant; negligible valuation impact and no trading signal for GOSS.

The single “A” code indicates an award, not a purchase or sale, so there is no insider buy/sell signal. With a $1.36 strike (near recent market levels), the option’s delta is modest; any future dilution is de minimis. Investors should treat this as routine board compensation and focus instead on clinical pipeline milestones and liquidity, as today’s filing does not provide earnings or operating updates.

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

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Milligan Sandra

(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)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
06/25/2025

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

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
Stock Option (Right to Buy)	$1.36	06/25/2025		A		115,000(1)		(2)	06/24/2035	Common Stock	115,000	$0	115,000	D

Explanation of Responses:

1. Award made pursuant to Non-Employee Director Compensation Program.

2. The entire number of shares subject to this option becomes fully vested and exercisable on the first to occur of (a) the first anniversary of the grant date or (b) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continued service on the board of directors of the Issuer through such vesting date.

Remarks:

	/s/ Jeff Boerneke, Attorney-in-Fact	06/26/2025
	** 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 the GOSS Form 4 filed on 06/26/2025 disclose?

It reported a grant of 115,000 stock options to director Sandra Milligan at an exercise price of $1.36.

Does Sandra Milligan now own any additional common shares of GOSS?

No common shares were acquired or sold; only derivative securities (options) were granted.

When do the granted GOSS options vest?

They fully vest on the earlier of one year after 06/25/2025 or the next annual shareholder meeting.

What is the expiration date of the options granted to the GOSS director?

The options expire on 06/24/2035.

Is this Form 4 filing considered material for investors?

It is generally viewed as routine compensation with minimal dilution and no immediate financial impact.