X0306 4 2021-09-09 0 0001783328 TScan Therapeutics, Inc. TCRX 0001860597 Silver Brian M. C/O TSCAN THERAPEUTICS, INC. 830 WINTER STREET WALTHAM MA 02451 0 1 0 0 Chief Financial Officer Voting Common Stock 2021-09-09 4 P 0 5885 8.4835 A 6885 D The price reported in Column 4 is a weighted average price. These securities were purchased in multiple transactions at prices ranging from $8.34 to $8.52, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of securities purchased at each separate price within the ranges set forth in this footnote (1) to this Form 4. /s/ Brian M. Silver 2021-09-13