Sec Form 3 Filing - Westphal Christoph H @ TScan Therapeutics, Inc. - 2021-07-15

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 Westphal Christoph H 2. Issuer Name and Ticker or Trading Symbol TScan Therapeutics, Inc. [ TCRX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O TSCAN THERAPEUTICS, INC., 830 WINTER STREET 3. Date of Earliest Transaction (MM/DD/YY) 07/15/2021 (Street) WALTHAM, MA02451 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 Voting Common Stock 914,634 D Voting Common Stock 121,951 I See footnote ( 1 )

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 ( 2 ) ( 2 ) ( 2 ) Voting Common Stock 641,848 I See footnote ( 3 ) Series B Preferred Stock ( 2 ) ( 2 ) ( 2 ) Voting Common Stock 332,594 I See footnote ( 3 ) Series C Preferred Stock ( 2 ) ( 2 ) ( 2 ) Voting Common Stock 171,063 I See footnote ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Westphal Christoph H C/O TSCAN THERAPEUTICS, INC. 830 WINTER STREET WALTHAM, MA02451 X X Signatures /s/ Christoph Westphal 07/15/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These shares are held by the Reporting Person's spouse. ( 2 )Each share of the Issuer's Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock is convertible into shares of the Issuer's Voting Common Stock on a 1 for 1 basis at the holder's election and will automatically convert immediately prior to the closing of the Issuer's initial public offering. These shares have no expiration date. ( 3 )These shares are held by Longwood Fund IV, L.P. ("Longwood"). The general partner of Longwood is Longwood Fund IV GP, LLC ("Longwood GP"). Longwood GP may be deemed to have sole voting and dispositive power over the shares held by Longwood. Each of Richard Aldrich and Christoph Westphal, M.D., Ph.D. (collectively, the "Managers") are managers of Longwood GP and may be deemed to share voting and dispositive power over of the shares held by Longwood. Each of Longwood GP and the Managers disclaim beneficial ownership of these shares and this report shall not be deemed an admission that any one of them is the beneficial owner of such shares for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

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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