Gossamer Bio director granted 115,000 stock options

Gossamer Bio, Inc. director Daniel Thomas O received a stock option award for 115,000 shares of common stock.

Rhea-AI Filing Summary

Gossamer Bio, Inc. director Daniel Thomas O received a stock option award for 115,000 shares of common stock. The option has a per-share exercise price of $0.1780 and expires on June 3, 2036. This grant was made under the company’s Non-Employee Director Compensation Program and represents compensation rather than an open-market purchase.

The entire option becomes fully vested and exercisable on the earlier of the first anniversary of the grant date or the next annual meeting of stockholders, provided he continues serving on the board through that vesting date. Following this grant, he holds 115,000 stock options directly.

Insights

Equity compensation analyst

Routine director stock option grant with standard vesting terms.

The filing shows Gossamer Bio granted director Daniel Thomas O 115,000 stock options at an exercise price of $0.1780 per share, expiring on June 3, 2036. The award is explicitly tied to the Non-Employee Director Compensation Program, indicating a standard board compensation practice.

The option vests in full on the earlier of the first anniversary of the grant or the next annual stockholder meeting, contingent on continued board service. There are no open-market buys or sells and no remaining derivative positions listed beyond this grant, so the transaction is best viewed as routine equity compensation with neutral signaling value for investors.

Insider Trade Summary

Grant/Award: 115,000 shares

Grant/Award 1 txn

Insider Daniel Thomas O

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	115,000	$0.00	$0.00

Holdings After Transaction: Stock Option (Right to Buy) — 115,000 contracts (Direct)

Footnotes (2)

1. F1. Award made pursuant to Non-Employee Director Compensation Program.
2. F2. 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.

Key Figures

Option grant size: 115,000 options Exercise price: $0.1780 per share Expiration date: June 3, 2036 +2 more

5 metrics

Option grant size 115,000 options Stock Option (Right to Buy) granted to director

Exercise price $0.1780 per share Exercise price of stock option

Expiration date June 3, 2036 Option expiration

Underlying shares 115,000 shares Common stock underlying the option

Post-transaction option holdings 115,000 options Total derivative holdings following grant

Key Terms

Stock Option (Right to Buy), Non-Employee Director Compensation Program, vested and exercisable, underlying security, +1 more

5 terms

Stock Option (Right to Buy) financial

"security_title: Stock Option (Right to Buy)"

Non-Employee Director Compensation Program financial

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

vested and exercisable financial

"becomes fully vested and exercisable on the first to occur"

underlying security financial

"underlying_security_title: Common Stock"

exercise price financial

"conversion_or_exercise_price: 0.1780"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Gossamer Bio (GOSS) director Daniel Thomas O receive in this Form 4?

He received a stock option to acquire 115,000 shares of Gossamer Bio common stock. The option was granted as part of the Non-Employee Director Compensation Program and represents equity-based board compensation rather than an open-market stock purchase.

What is the exercise price of the new Gossamer Bio (GOSS) stock options?

The stock options have an exercise price of $0.1780 per share. This means the director can buy Gossamer Bio common shares at $0.1780 once the option has vested, regardless of the market price at that time.

When do the newly granted Gossamer Bio (GOSS) stock options vest?

The entire 115,000-share option becomes fully vested on the earlier of the first anniversary of the grant date or the next annual stockholder meeting. Vesting requires Daniel Thomas O to remain on Gossamer Bio’s board through that vesting date.

When do Daniel Thomas O’s Gossamer Bio (GOSS) stock options expire?

The options expire on June 3, 2036. After that expiration date, any unexercised portion of the 115,000-share option can no longer be used to purchase Gossamer Bio common stock at the $0.1780 exercise price.

Is this Gossamer Bio (GOSS) Form 4 a stock purchase or compensation grant?

It is a compensation grant, not an open-market stock purchase. The filing describes a stock option award under the Non-Employee Director Compensation Program, providing the director with the right to buy shares in the future at a fixed exercise price.

How many Gossamer Bio (GOSS) stock options does Daniel Thomas O hold after this transaction?

After this transaction, he holds 115,000 stock options directly. This total matches the size of the new grant, indicating the reported derivative holdings consist of this single option position following the award.

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

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Accepted by SEC EDGAR 06/05/2026 - 04:30 PM EDT Learn about SEC filing dates

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
Estimated average burden
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^*

Daniel Thomas O

(Last) (First) (Middle)

3115 MERRYFIELD ROW, SUITE 120

(Street)

SAN DIEGO CALIFORNIA 92121

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/04/2026

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

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

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

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)	$0.178	06/04/2026		A		115,000(1)		(2)	06/03/2036	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/ Christian Waage, Attorney-in-Fact	06/05/2026
	** 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.
* Form 4: SEC 1474 (03-26)