Who invested in X4 Pharmaceuticals

2 rounds we have observed, with the 6 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.

Biotech

Funding summaryUpdated 26 Oct 2026

$193Mraised across 2 rounds since 2015, from 2 sources

$37MVenture$155MRound

Latest round: Round, $155MOct 2025
Step-upi: 4.1×
Investors: 6

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.

201520172019202120232025

$37MVenture$155MRound

First round: Venture, $37M
Biggest round: $155M
Between rounds: 10.1 years

The rounds

Oct 2025
Round$155M6 new
Source recordedSEC filing: $85M sold, first sale Aug 2025
Aug 2015
Venture$37M
No investor was named in the report.
From a historical funding recordSEC filing: $37M sold, first sale Aug 2015

Founders and team

From X4 Pharmaceuticals's own website: 3 on the team.

Adam MostafaChief Financial Officer
David KirskeChief Financial Officer
Mark BaldryChief Commercial Officer

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.

Venture2015Round2025

New Enterprise Associates

OrbiMed

Cormorant Asset Management

Hercules CapitalSV Health InvestorsBain Capital Life Sciences

Everyone who backed them

New Enterprise AssociatesVC firm1round

OrbiMedPrivate equity1round

Cormorant Asset ManagementPrivate equity1round

Hercules CapitalVenture debt1round

SV Health InvestorsVC firm1round

Bain Capital Life SciencesPrivate equity1round

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

Also claim to have backed them

This firm lists X4 Pharmaceuticals as a portfolio company on their own website, but no report of a round names it. They are the firms' own claims, kept apart from the rounds above.

K2 HealthVenturesPrivate equityPer its own site

Quick answers about X4 Pharmaceuticals

Who invested in X4 Pharmaceuticals?

X4 Pharmaceuticals's investors include New Enterprise Associates, OrbiMed, Cormorant Asset Management, Hercules Capital and SV Health Investors, and 1 more on record.

How much has X4 Pharmaceuticals raised?

X4 Pharmaceuticals has raised $193M across 2 rounds since 2015.

When did X4 Pharmaceuticals last raise?

X4 Pharmaceuticals's most recent round was an Undisclosed round of $155M in Oct 2025.

What was X4 Pharmaceuticals's biggest round?

Its most recent round, $155M in Oct 2025, is also its largest on record.

Who backed X4 Pharmaceuticals first?

X4 Pharmaceuticals's first round on record, in Oct 2025, was backed by New Enterprise Associates, OrbiMed and Cormorant Asset Management and 3 others.