Mpm Asset Management Llc - May 22, 2023 Form 4 Insider Report for TCR2 THERAPEUTICS INC. (TCRR)

Role: 10%+ Owner
Signature: /s/ Luke Evnin, member of MPM Asset Management LLC
Stock symbol: TCRR
Transactions as of: May 22, 2023
Transactions value $: -$1
Form type: 4
Date filed: 5/24/2023, 04:39 PM

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	TCRR	Common Stock	Exercise of in-the-money or at-the-money derivative security	$132K	+178K	+91%	$0.74	374K	May 22, 2023	Direct	F1
transaction	TCRR	Common Stock	Sale	-$132K	-70.2K	-18.75%	$1.88	304K	May 22, 2023	Direct	F1
holding	TCRR	Common Stock						3.37M	May 22, 2023	See Footnote	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	TCRR	Common Stock Warrant (Right To Buy)	Exercise of in-the-money or at-the-money derivative security	$0	-42.8K	-100%	$0.00^*	0	May 22, 2023	Common Stock	42.8K	$0.74	Direct	F1
transaction	TCRR	Common Stock Warrant (Right to Buy)	Exercise of in-the-money or at-the-money derivative security	$0	-136K	-100%	$0.00^*	0	May 22, 2023	Common Stock	136K	$0.74	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	On May 22, 2023, MPM Asset Management LLC ("AM LLC") exercised warrants to purchase 178,269 shares of the Issuer's common stock for $0.74 a share. AM LLC paid the exercise price on a cashless basis, resulting in the Issuer's withholding of 70,170 of the warrant shares to satisfy the exercise price and issuing to AM LLC the remaining 108,099 shares.
F2	The shares are held as follows: 3,056,272 by MPM BioVentures 2014, L.P. ("BV 2014"), 203,846 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)") and 110,859 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"). MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B) and BV LLC is the manager of AM BV 2014. Luke Evnin is a managing director of BV LLC and disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interest therein.

Content

On May 22, 2023, MPM Asset Management LLC ("AM LLC") exercised warrants to purchase 178,269 shares of the Issuer's common stock for $0.74 a share. AM LLC paid the exercise price on a cashless basis, resulting in the Issuer's withholding of 70,170 of the warrant shares to satisfy the exercise price and issuing to AM LLC the remaining 108,099 shares.

The shares are held as follows: 3,056,272 by MPM BioVentures 2014, L.P. ("BV 2014"), 203,846 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)") and 110,859 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"). MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B) and BV LLC is the manager of AM BV 2014. Luke Evnin is a managing director of BV LLC and disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interest therein.