Gossamer Bio Inc.

03/20/2026 | Press release | Distributed by Public on 03/20/2026 14:22

Statement of Changes in Beneficial Ownership (Form 4)

FORM 4
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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES 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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(Print or Type Responses)
1. Name and Address of Reporting Person *
Aranda Richard
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)
Chief Medical Officer
(Last) (First) (Middle)
3115 MERRYFIELD ROW, SUITE 120
3. Date of Earliest Transaction (Month/Day/Year)
03/19/2026
(Street)
SAN DIEGO, CA 92121
4. If Amendment, Date 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
(City) (State) (Zip)
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
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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 control number. SEC 1474 (9-02)
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 Underlying Securities
(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 of Derivative Security: 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) $2.88 03/19/2026 D(1) 562,500 (2) 01/01/2036 Common Stock 562,500 (1) 0 D
Stock Option (Right to Buy) $1.13 03/19/2026 D(1) 572,000 (2) 03/03/2035 Common Stock 572,000 (1) 0 D
Stock Option (Right to Buy) $0.97 03/19/2026 D(1) 487,500 (2) 01/01/2034 Common Stock 487,500 (1) 0 D
Stock Option (Right to Buy) $0.838 03/19/2026 D(1) 162,500 (2) 11/19/2033 Common Stock 162,500 (1) 0 D
Stock Option (Right to Buy) $1.21 03/19/2026 D(1) 157,500 (2) 03/19/2033 Common Stock 157,500 (1) 0 D
Stock Option (Right to Buy) $2.16 03/19/2026 D(1) 157,500 (2) 12/06/2032 Common Stock 157,500 (1) 0 D
Stock Option (Right to Buy) $1.36 03/19/2026 D(1) 126,667 (2) 01/05/2032 Common Stock 126,667 (1) 0 D
Stock Option (Right to Buy) $1.36 03/19/2026 D(1) 20,000 (2) 06/21/2031 Common Stock 20,000 (1) 0 D
Stock Option (Right to Buy) $1.36 03/19/2026 D(1) 40,000 (2) 02/25/2031 Common Stock 40,000 (1) 0 D
Stock Option (Right to Buy) $1.36 03/19/2026 D(1) 22,784 (2) 02/14/2030 Common Stock 22,784 (1) 0 D
Stock Option (Right to Buy) $1.36 03/19/2026 D(1) 9,167 (2) 12/23/2029 Common Stock 9,167 (1) 0 D
Stock Option (Right to Buy) $1.36 03/19/2026 D(1) 30,000 (2) 03/25/2029 Common Stock 30,000 (1) 0 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 562,500 (2) 01/01/2036 Common Stock 562,500 (1) 562,500 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 572,000 (2) 03/03/2035 Common Stock 572,000 (1) 572,000 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 487,500 (2) 01/01/2034 Common Stock 487,500 (1) 487,500 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 162,500 (2) 11/19/2033 Common Stock 162,500 (1) 162,500 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 157,500 (2) 03/19/2033 Common Stock 157,500 (1) 157,500 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 157,500 (2) 12/06/2032 Common Stock 157,500 (1) 157,500 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 126,667 (2) 01/05/2032 Common Stock 126,667 (1) 126,667 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 20,000 (2) 06/21/2031 Common Stock 20,000 (1) 20,000 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 40,000 (2) 02/25/2031 Common Stock 40,000 (1) 40,000 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 22,784 (2) 02/14/2030 Common Stock 22,784 (1) 22,784 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 9,167 (2) 12/23/2029 Common Stock 9,167 (1) 9,167 D
Stock Option (Right to Buy) $0.45 03/19/2026 A(1) 30,000 (2) 03/25/2029 Common Stock 30,000 (1) 30,000 D

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Aranda Richard
3115 MERRYFIELD ROW, SUITE 120
SAN DIEGO, CA 92121
Chief Medical Officer

Signatures

/s/ Jeff Boerneke, Attorney-in-Fact 03/20/2026
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Effective as of March 19, 2026 (the "Repricing Date"), the Issuer approved a one-time repricing of certain outstanding stock options (the "Repriced Options") granted under the Issuer's 2019 Incentive Award Plan (the "2019 Plan"), which reduced the per share exercise price of each Repriced Option to $0.45 (the "Option Repricing"). Except as modified by the Option Repricing, all other terms and conditions of the Repriced Options, including, without limitation, any provisions with respect to vesting and term of the Repriced Options, remain in full force and effect.
(2) This stock option award was issued pursuant to the 2019 Plan and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.
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