Sec Form 4 Filing - Gujrathi Sheila @ Gossamer Bio, Inc. - 2019-02-12

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Gujrathi Sheila 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 X __ Officer (give title below) _____ Other (specify below) President & CEO (Last) (First) (Middle) 3013 SCIENCE PARK ROAD 3. Date of Earliest Transaction (MM/DD/YY) 02/12/2019 (Street) SAN DIEGO, CA92121 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 02/12/2019 C 62,030 A 4,038,242 ( 2 ) I By family trust

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Series A Preferred Stock ( 1 ) 02/12/2019 C 223,182 ( 1 ) ( 1 ) Common Stock 49,596 ( 1 ) 0 I By family trust Series B Preferred Stock ( 1 ) 02/12/2019 C 55,957 ( 1 ) ( 1 ) Common Stock 12,434 ( 1 ) 0 I By family trust

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Gujrathi Sheila 3013 SCIENCE PARK ROAD SAN DIEGO, CA92121 X President & CEO Signatures /s/ Jeff Boerneke, Attorney-in-Fact 02/12/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The shares of the Issuer's Series A Preferred Stock and Series B Preferred Stock automatically converted into shares of the Issuer's Common Stock, for no additional consideration, at a ratio of 4.5 to one share, immediately prior to the consummation of the Issuer's initial public offering. The Series A Preferred Stock and Series B Preferred Stock had no expiration date. ( 2 )Includes 2,595,584 shares subject to forfeiture, which shares will vest in equal monthly installments as set forth in the restricted stock agreements between the Issuer and Reporting Person so that all of the shares will be released from the forfeiture restriction on January 4, 2023, subject to the Reporting Person's continuous service to the Issuer on each such vesting date. The shares are also subject to certain accelerated vesting provisions as set forth in more detail in the employment agreement between the Issuer and the Reporting Person.

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.