Arvin Yang - Jan 13, 2023 Form 4 Insider Report for Mersana Therapeutics, Inc. (MRSN)

Role: SVP, Chief Medical Officer
Signature: /s/Alejandra Carvajal, as attorney-in-fact
Stock symbol: MRSN
Transactions as of: Jan 13, 2023
Transactions value $: -$12,680
Form type: 4
Date filed: 1/18/2023, 07:29 PM
Previous filing: Dec 2, 2022

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MRSN	Common Stock	Options Exercise	$0	+7.08K	+27.3%	$0.00	33K	Jan 14, 2023	Direct	F1
transaction	MRSN	Common Stock	Sale	-$12.7K	-2.21K	-6.69%	$5.74	30.8K	Jan 17, 2023	Direct	F2, F3

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	MRSN	Stock option (right to buy)	Award	$0	+218K		$0.00	218K	Jan 13, 2023	Common Stock	218K	$6.06	Direct	F4
transaction	MRSN	Restricted stock unit	Award	$0	+48.3K		$0.00	48.3K	Jan 13, 2023	Common Stock	48.3K		Direct	F5, F6
transaction	MRSN	Restricted stock unit	Options Exercise	$0	-7.08K	-25%	$0.00	21.2K	Jan 14, 2023	Common Stock	7.08K		Direct	F5, F7

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

Explanation of Responses:

Id	Content
F1	Represents shares of common stock received upon the vesting of a portion of the restricted stock units ("RSUs") awarded to the Reporting Person on January 14, 2022.
F2	Represents the sale of shares of common stock to satisfy the Reporting Person's tax withholding obligations in connection with the service-based vesting and settlement of the RSUs reported above. These sales were mandated by the Issuer's election under its equity incentive plans to require the Reporting Person to sell a number of shares of common stock needed to satisfy his tax withholding obligations and does not represent a discretionary trade by the Reporting Person.
F3	The price reported is a weighted average sales price. The shares were sold in multiple transactions at prices ranging from $5.74 to $5.78, 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 shares sold at each separate price within the ranges set forth in this footnote.
F4	The option shall vest in equal quarterly installments over four years from the date of grant.
F5	Each RSU represents the contingent right to receive one share of common stock of the Issuer.
F6	The RSUs shall vest in equal annual installments over four years from the date of grant.
F7	25% of the total number of RSUs granted vested on January 14, 2023, and the remainder shall vest thereafter in equal annual installments over the next three years.