MRSN

Mersana Therapeutics, Inc.

Total Trades

105

Buys

9

Sells

48

Largest Trade

N/A

Insiders

10

Institutional Funds

39

Inst. Value

$1M+

Activist Filings

46

Insider Trades

InsiderTitleTypeValueSharesPriceDate
Lowinger Timothy BChief Science & Te…SELL$15K–$50K5K$5.92Jan 19, 2022
Mandelia AshishVP, ControllerSELL$1K–$15K2K$5.92Jan 19, 2022
Mandelia AshishVP, ControllerEXERCISEN/A5KJan 19, 2022
Hack Andrew A. F.DirectorBUY$1M+815K$6.15Jan 4, 2022
Hack Andrew A. F.DirectorBUY$1M+875K$5.75Jan 3, 2022
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Institutional Ownership

13F filings as of Dec 31, 2025 · 39 funds holding

Activist & 5%+ Owners

SC 13D/13G filings — investors holding 5%+ of outstanding shares

The Vanguard Group

SC 13G/A · Jan 30, 2026

4.2%

210K shares

Nextech Crossover I GP S.a. r.l.

SC 13G/A · Jan 9, 2026

0.0%

0 shares

0.0%

0 shares

683 Capital Management, LLC

SC 13G · Nov 24, 2025

5.5%

273K shares

Schonfeld Strategic Advisors LLC

SC 13G · Nov 14, 2025

5.5%

274K shares

2.6%

132K shares

Schonfeld Strategic Advisors LLC

SC 13G/A · Aug 14, 2025

4.5%

5.7M shares

BlackRock, Inc.

SC 13G/A · Jul 17, 2025

3.0%

3.8M shares

2.9%

3.6M shares

Schonfeld Strategic Advisors LLC

SC 13G · May 15, 2025

6.1%

7.6M shares

EcoR1 Capital, LLC

SC 13G/A · May 15, 2025

0.0%

0 shares

The Vanguard Group

SC 13G/A · Apr 30, 2025

6.7%

8.4M shares

BlackRock, Inc.

SC 13G/A · Apr 17, 2025

6.7%

8.3M shares

8.3%

10.3M shares

BlackRock, Inc.

SC 13G/A · Feb 5, 2025

8.0%

9.2M shares

Nextech Crossover I GP S.a. r.l.

SC 13G/A · Dec 26, 2024

10.4%

12.1M shares

EcoR1 Capital, LLC

SC 13G/A · Dec 24, 2024

10.0%

11.6M shares

2.7%

3.3M shares

Nextech Crossover I SCSp

SC 13G/A · Nov 14, 2024

9.8%

12.1M shares

Balyasny Asset Management L.P. 2

SC 13G/A · Nov 14, 2024

0.4%

536K shares

SilverArc Capital Management, LLC

SC 13G/A · Oct 15, 2024

1.4%

1.8M shares

Nextech Crossover I SCSp

SC 13G · May 17, 2024

5.1%

6.2M shares

9.4%

11.3M shares

SilverArc Capital Management, LLC

SC 13G · Feb 15, 2024

5.3%

6.4M shares

OrbiMed Capital LLC

SC 13G/A · Feb 14, 2024

0.0%

0 shares

Avoro Capital Advisors LLC

SC 13G/A · Feb 14, 2024

0.0%

0 shares

Balyasny Asset Management L.P. 2

SC 13G · Feb 14, 2024

8.0%

9.7M shares

The Vanguard Group - 23-1945930

SC 13G · Feb 13, 2024

5.2%

6.2M shares

BlackRock, Inc.

SC 13G/A · Jan 29, 2024

6.5%

7.8M shares

8.5%

9.7M shares

EcoR1 Capital, LLC

SC 13G · Jul 27, 2023

16.9%

19.4M shares

OrbiMed Capital LLC

SC 13G · Feb 14, 2023

7.1%

7.1M shares

BB Biotech AG

SC 13G/A · Feb 14, 2023

4.1%

4.1M shares

Avoro Capital Advisors LLC

SC 13G/A · Feb 14, 2023

7.6%

7.5M shares

Rho Ventures V, L.P.

SC 13G/A · Feb 13, 2023

0.0%

0 shares

BlackRock, Inc.

SC 13G/A · Jan 31, 2023

7.5%

7.5M shares

Millennium Management LLC

SC 13G/A · Jan 19, 2023

3.7%

3.7M shares

3.4%

3.3M shares

3.9%

3.3M shares

Millennium Management LLC

SC 13G · Feb 17, 2022

5.2%

3.7M shares

BlackRock, Inc.

SC 13G · Jan 27, 2022

10.4%

7.5M shares

BlackRock, Inc.

SC 13G/A · Jan 26, 2022

10.4%

7.5M shares

4.5%

3.3M shares