Sec Form 3 Filing - Andersson Claus A. @ IO Biotech, Inc. - 2021-11-04

FORM 3 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

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1. Name and Address of Reporting Person Andersson Claus A. 2. Issuer Name and Ticker or Trading Symbol IO Biotech, Inc. [ IOBT] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O IO BIOTECH, INC., OLE MAALOES VEH 3 3. Date of Earliest Transaction (MM/DD/YY) 11/04/2021 (Street) COPENHAGEN, G72200 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

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 B Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 1,361,660 I See footnote ( 3 ) Series C Preferred Stock ( 2 ) ( 2 ) ( 2 ) Common Stock 354,830 I See footnote ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Andersson Claus A. C/O IO BIOTECH, INC. OLE MAALOES VEH 3 COPENHAGEN, G72200 X Signatures /s/ Brian Burkavage, Attorney-in-Fact for Claus Andersson 11/04/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Upon the closing of the Issuer's initial public offering ("IPO"), each share of Series B Preferred Stock beneficially owned by the reporting person will automatically convert, for no additional consideration, into the number of shares of Common Stock reported in Column 3. These shares of Series B Preferred Stock have no expiration date. ( 2 )Upon the closing of the Issuer's initial public offering ("IPO"), each share of Series C Preferred Stock beneficially owned by the reporting person will automatically convert, for no additional consideration, into the number of shares of Common Stock reported in Column 3. These shares of Series C Preferred Stock have no expiration date. ( 3 )Sunstone Life Science Ventures Fund III K/S ("Sunstone Fund III"). Sunstone LSV General Partner III ApS ("Sunstone LSV GP III") is the general partner of Sunstone Fund III and has voting and dispositive power over all of the shares of held by Sunstone Fund III. The reporting person is a General Partner of Sunstone Life Science Ventures A/S and a member of the executive board of Sunstone LSV GP III, and shares voting and dispositive power with respect to the shares held by Sunstone Fund III. The reporting person disclaims beneficial ownership of the shares held directly by Sunstone Fund III except to the extent of his pecuniary interest therein.

Remarks: Exhibit List: Exhibit 24 - Power of Attorney

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).

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