Who invested in Mersana Therapeutics

8 rounds we have observed, with the 13 investors named in them. Every figure came from a named source, and where the company reported a raise to the SEC itself, that is shown beside it.

BiotechHealthcare

Funding summaryUpdated 26 Oct 2026

$148Mraised across 8 rounds since 2005, from 8 sources

$21MVenture$2.5MDebt$10MDebt$27MSeries A$5.0MSeries A$15MSeries A$35MSeries B$33MSeries C

Latest round: Series C, $33MJun 2016
Biggest round: $35MSeries B · Mar 2015
Investors: 13

See who backed them

The funding story

Each circle is a round, placed by date and sized by amount. The line above is the running total.

20072009201120132015

$21MVenture$2.5MDebt$10MDebt$27MSeries A$5.0MSeries A$15MSeries A$35MSeries B$33MSeries C

First round: Venture, $21M
Biggest round: $35M
Usual gap between rounds: 14 months

The rounds

Jun 2016
Series C$33M1 new
- Wellington Management
Reported by FiercebiotechSEC filing: $33M sold, first sale Jun 2016
Mar 2015
Series B$35M2 new3 returning
- New Enterprise Associates
- F-Prime Capital
- Pfizer
- Rock Springs Capital
- Elliott Sigal
From a historical funding recordSEC filing: $10M sold, first sale Feb 2015
Apr 2014
Series A$15M3 returning
From a historical funding recordSEC filing: $15M sold, first sale Sept 2013
Oct 2013
Series A$5.0M2 returning
- New Enterprise Associates
- Fidelity Biosciences
Reported by boston.citybizlist.comSEC filing: $5.0M sold, first sale Sept 2013
Jul 2012
Series A$27M2 new3 returning
Reported by finsmes.comSEC filing: $13M sold, first sale Jul 2012
Apr 2012
Debt$10M
No investor was named in the report.
Reported by sec.govSEC filing: $10M sold, first sale Apr 2011
Feb 2010
Debt$2.5M
No investor was named in the report.
From a historical funding recordSEC filing: $2.5M sold, first sale Jan 2010
Nov 2005
Venture$21M8 new
Reported by mersana.com

Founders and team

From the SEC filings it signed: 6 on the team.

Anna ProtopapasExecutive Officer, Directori
Donald BergstromExecutive Officeri
Eva JackExecutive Officeri
Michael J. KaufmanExecutive Officeri
Timothy LowingerExecutive Officeri
Wayne J. FosterExecutive Officeri

On the board, as filediDavid MottElaine J. JonesSara J. NayeemThomas J. Beck

Who was in which round

The busiest backers across the latest rounds. A filled square is a round they joined; a dark one, a round they led.

Venture2005Debt2010Debt2012Series A2012Series A2013Series A2014Series B2015Series C2016

New Enterprise Associates

F-Prime CapitalFidelity Biosciences

Pfizer

ProQuest Investments

Wellington Management

Rho Capital PartnersHarris & Harris Group

Rock Springs Capital

PureTech Health

Everyone who backed them

New Enterprise AssociatesVC firm4rounds

F-Prime CapitalVC firm4rounds

Fidelity BiosciencesInvestment firm4rounds

PfizerCorporate VC2rounds

ProQuest InvestmentsVC firm2rounds

Wellington ManagementVC firm1round

Rho Capital PartnersPrivate equity1round

Harris & Harris GroupGrowth equity1round

Rock Springs CapitalHedge fund1round

PureTech HealthVC firm1round

Lansing Brown InvestmentsVC firm1round

Cape Family Fundno record of our own yet1round

Elliott Sigalno record of our own yet1round

Missing a round, or an investor who was in one? Tell us.

Also claim to have backed them

These 2 firms list Mersana Therapeutics as a portfolio company on their own websites, but no report of a round names them. They are the firms' own claims, kept apart from the rounds above.

Lightstone VenturesVC firmPer its own site

Nextech InvestPrivate equityPer its own site

Quick answers about Mersana Therapeutics

Who invested in Mersana Therapeutics?

Mersana Therapeutics's investors include New Enterprise Associates, F-Prime Capital, Fidelity Biosciences, Pfizer and ProQuest Investments, and 8 more on record.

How much has Mersana Therapeutics raised?

Mersana Therapeutics has raised $148M across 8 rounds since 2005.

When did Mersana Therapeutics last raise?

Mersana Therapeutics's most recent round was a Series C of $33M in Jun 2016.

What was Mersana Therapeutics's biggest round?

Mersana Therapeutics's largest round on record is $35M (Series B), in Mar 2015.

Who backed Mersana Therapeutics first?

Mersana Therapeutics's first round on record, in Nov 2005, was backed by F-Prime Capital, Rho Capital Partners and Harris & Harris Group and 5 others.