Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share (MRSN)

Q: What does CUSIP 59045L106 represent in this 13F holders report?

CUSIP 59045L106 is the security identifier for MRSN - Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share used to aggregate holder disclosures.

Q: How many institutions held MRSN - Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share in Q1 2022?

127 institutional investors reported MRSN - Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share for Q1 2022. Use the holders table for investor-level position and value details.

CUSIP: 59045L106

Q1 2022 13F Holders as of 31 Mar 2022

Security type / class: Equity / Common Stock, par value $0.0001 per share
Total 13F shares: 80,872,131
Total 13F value: $322,721,381
Share change: +9,683,076
Put/Call ratio: 455%
SEC-reported price per share: $3.99
Number of holders: 127
Value change: +$33,055,220
Number of buys: 66
Number of sells: 53
Shares outstanding: 4,992,318

Security key

59045L106

Report period

Q1 2022

Institutions

127

Top holders

MRSN full security history Ownership snapshot Full 13F holder table Newer quarter: Q4 2025 Mersana Therapeutics, Inc. SEC filings Mersana Therapeutics, Inc. company facts

Broader feeds

Latest 13F filings Latest 13D/G filings Investors directory

Reporting periods

Holder history for CUSIP 59045L106

Newer quarter: Q4 2025

Recent filing periods:

Q1 2026 Q4 2025

Ownership snapshot

Top reported holders of MRSN - Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader

BlackRock Finance, Inc.

Disclosed value leader

BlackRock Finance, Inc.

Comparable rows

15/15

Latest evidence

31 Dec 2021

13F Lead comparable stake: 150% Showing 1-6 of 15 holder rows.

Quick read

BlackRock Finance, Inc. leads the comparable SEC ownership view at 150%.

15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens BlackRock Finance, Inc.'s linked filing trail.

Comparable ownership Top 5

BlackRock Finance, Inc. 150%

Avoro Capital Advisors LLC 136%

Bain Capital Life Sciences Invest... 108%

WELLINGTON MANAGEMENT GROUP LLP 100%

Sarissa Capital Management LP 86%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-6 of 15 holder rows

Holder	Evidence	Ownership %	Position	12M Net Δ	As of
BlackRock Finance, Inc.	13F Company 13F	150%	$46,520,000 7,479,229 shares	—	31 Dec 2021
Avoro Capital Advisors LLC	13F Company 13F	136%	$42,296,000 6,800,000 shares	—	31 Dec 2021
Bain Capital Life Sciences Investors, LLC	13F Company 13F	108%	$33,499,000 5,385,667 shares	—	31 Dec 2021
WELLINGTON MANAGEMENT GROUP LLP	13F Company 13F	100%	$31,207,000 5,017,078 shares	—	31 Dec 2021
Sarissa Capital Management LP	13F Company 13F	86%	$26,742,000 4,299,297 shares	—	31 Dec 2021
STATE STREET CORP	13F Company 13F	85%	$26,252,000 4,220,557 shares	—	31 Dec 2021

How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

13F holder rows

Institutional holders as of Q1 2022

Investor-level positions for this CUSIP, loaded as an interactive table.

Institutions

127

80,872,131

Rows available

127

Investor	Option	Weight %	Change %	SEC-reported value	* Price	Shares	Share Change	Activity	Report Period

^* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.

Compare Q1 2022 vs Q4 2025 Across Filers

Q4 2025 holders

Q1 2022 holders

127

Holder diff

124

Investor	Q4 2025 Shares	Q1 2022 Shares	Share Diff	Share Chg %	Q4 2025 value	Q1 2022 value	Value change	Value Chg %

Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).

Quarterly Holders Trend

Quarterly Value Trend

Quarterly Shares Trend