EcoR1 Capital, LLC

13F Holdings History for Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share (MRSN)

Symbol: MRSN on Nasdaq
Investment type: Equity / Common Stock, par value $0.0001 per share
Latest Disclosed Ownership: 0 shares
Security Ownership: 0%

Shares, Excluding Options vs Price

Value, Excluding Options

EcoR1 Capital, LLC ownership in Mersana Therapeutics, Inc. Common Stock, par value $0.0001 per share (MRSN)

2025-05-15 - EcoR1 Capital, LLC has filed an SCHEDULE 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 0 shares of Mersana Therapeutics, Inc. Common Stock, par value $0.0001 per share (MRSN). This represents 0% percent ownership of the company. In their previous filing dated 2024-12-23, EcoR1 Capital, LLC had reported owning 11.6M shares, indicating a decrease of -100% percent.

Reporting Name	Ownership %	Change	Value $	Shares owned	Change	Activity %	Price	Form	Report date	Filed at
EcoR1 Capital, LLC	0%	-99.9%		0	-11,578,447	-100%	$0.30	13G/A	3/31/2025	15 May 2025 14:16:44
EcoR1 Capital, LLC	9.99%		$3.47M	11.6M			$0.30	13G/A	12/19/2024	23 Dec 2024 19:50:22

Holdings date	Weight	Change	Value $	Shares	Change	Activity %	Price	All Holders
3/31/2025		-0.65%	$0	0	-11,328,000	-100%		Q1 2025
12/31/2024	0.65%	-0.46%	$16.2M	11.3M	-8,036,688	-41.5%	$1.43	Q4 2024
9/30/2024	1.25%		$36.6M	19.4M			$1.89	Q3 2024
6/30/2024	1.19%		$38.9M	19.4M			$2.01	Q2 2024
3/31/2024	2.2%		$86.8M	19.4M			$4.48	Q1 2024
12/31/2023	1.17%		$44.9M	19.4M			$2.32	Q4 2023
9/30/2023	0.83%	+0.83%	$24.6M	19.4M	+19,364,688	NEW	$1.27	Q3 2023
9/30/2022		-0.05%	$0	0	-310,960	-100%		Q3 2022
6/30/2022	0.05%	0%	$1.44M	311K	-15,618	-4.78%	$4.62	Q2 2022
3/31/2022	0.04%	+0.04%	$1.3M	327K	+326,578	NEW	$3.99	Q1 2022
9/30/2019		-0.57%	$0	0	-1,392,231	-100%		Q3 2019
6/30/2019	0.57%	-0.37%	$5.64M	1.39M	-907,769	-39.5%	$4.05	Q2 2019
3/31/2019	1.12%	+1.12%	$12.1M	2.3M	+2,300,000	NEW	$5.26	Q1 2019
12/31/2018		-0.45%	$0	0	-495,618	-100%		Q4 2018
9/30/2018	0.45%	+0.45%	$4.96M	496K	+495,618	NEW	$10.00	Q3 2018

* Reported Price is the price of the security as of the portfolio date. This value is significant in that it is the last known price at which the security was still held.
An asterisk sign (*) next to the price indicates that the price is likely invalid.