# Who Invests With EcoR1 Capital: 31 Co-Investors (2026) > The 31 investors that have backed two or more of the same startups as EcoR1 Capital, by kind: vc firms, private equity and asset managers and growth funds. Source: https://millionrounds.com/portfolio-maps/ecor1-capital-co-investors (Millionrounds; every figure on the page links to its filing or article) ## VC firms 20 - [Fidelity](https://millionrounds.com/fund/fidelity) - [Alexandria Real Estate Equities](https://millionrounds.com/fund/alexandria) - [Redmile Group](https://millionrounds.com/fund/redmile-group) - [Omega Funds](https://millionrounds.com/fund/omega-funds) - [Samsara BioCapital](https://millionrounds.com/fund/samsara-biocapital) - [Casdin Capital](https://millionrounds.com/fund/casdin-capital) - [ARCH Venture Partners](https://millionrounds.com/fund/arch-venture-partners) - [The Column Group](https://millionrounds.com/fund/the-column-group) - [New Enterprise Associates](https://millionrounds.com/fund/new-enterprise-associates) - [*BP* BVF Partners](https://millionrounds.com/fund/bvf-partners) - [Boxer Capital](https://millionrounds.com/fund/boxer-capital) - [Wellington Management](https://millionrounds.com/fund/wellington-management) - [Polaris Partners](https://millionrounds.com/fund/polaris-partners) - [Khosla Ventures](https://millionrounds.com/fund/khosla-ventures) - [Third Rock Ventures](https://millionrounds.com/fund/third-rock-ventures) - [General Catalyst](https://millionrounds.com/fund/general-catalyst) - [Cormorant Capital](https://millionrounds.com/fund/cormorant-capital) - [6 Dimensions Capital](https://millionrounds.com/fund/6-dimensions-capital) - [Novartis](https://millionrounds.com/fund/novartis) - [Deerfield](https://millionrounds.com/fund/deerfield) ## Private equity and asset managers 8 - [OrbiMed](https://millionrounds.com/fund/orbimed) - [Invus](https://millionrounds.com/fund/invus) - [Foresite Capital](https://millionrounds.com/fund/forsite-capital) - [Arch](https://millionrounds.com/fund/arch) - [ArrowMark Partners](https://millionrounds.com/fund/arrowmark-partners) - [Vivo Capital](https://millionrounds.com/fund/vivo-capital) - [RA Capital Management](https://millionrounds.com/fund/ra-capital-management) - [Cormorant Asset Management](https://millionrounds.com/fund/cormorant-asset-management) ## Growth funds 3 - [Fidelity Management and Research Company](https://millionrounds.com/fund/fidelity-management-and-research-company) - [*JC* Janus Capital Group](https://millionrounds.com/fund/janus-capital-group) - [Goldbell Group](https://millionrounds.com/fund/polaris) ## Segment by segment ### VC firms 20 investors - [**Fidelity**](https://millionrounds.com/fund/fidelity) VC firm United States 10 backed - [**Alexandria Real Estate Equities**](https://millionrounds.com/fund/alexandria) VC firm United States 8 backed - [**Redmile Group**](https://millionrounds.com/fund/redmile-group) VC firm United States 6 backed - [**Omega Funds**](https://millionrounds.com/fund/omega-funds) VC firm United States 6 backed - [**Samsara BioCapital**](https://millionrounds.com/fund/samsara-biocapital) VC firm United States 5 backed - [**Casdin Capital**](https://millionrounds.com/fund/casdin-capital) VC firm United States 4 backed - [**ARCH Venture Partners**](https://millionrounds.com/fund/arch-venture-partners) VC firm United States 4 backed - [**The Column Group**](https://millionrounds.com/fund/the-column-group) VC firm United States 3 backed ### Private equity and asset managers 8 investors - [**OrbiMed**](https://millionrounds.com/fund/orbimed) Private equity United States 7 backed - [**Invus**](https://millionrounds.com/fund/invus) Private equity United States 5 backed - [**Foresite Capital**](https://millionrounds.com/fund/forsite-capital) Private equity United States 4 backed - [**Arch**](https://millionrounds.com/fund/arch) Hedge fund - 3 backed - [**ArrowMark Partners**](https://millionrounds.com/fund/arrowmark-partners) Private equity United States 2 backed - [**Vivo Capital**](https://millionrounds.com/fund/vivo-capital) Private equity United States 2 backed - [**RA Capital Management**](https://millionrounds.com/fund/ra-capital-management) Private equity United States 2 backed - [**Cormorant Asset Management**](https://millionrounds.com/fund/cormorant-asset-management) Private equity United States 2 backed ### Growth funds 3 investors - [**Fidelity Management and Research Company**](https://millionrounds.com/fund/fidelity-management-and-research-company) Growth fund United States 3 backed - [*JC* **Janus Capital Group**](https://millionrounds.com/fund/janus-capital-group) Growth fund United States 2 backed - [**Goldbell Group**](https://millionrounds.com/fund/polaris) Growth fund Singapore 2 backed **How this map is made.** Every investor here has backed two or more of the same startups as EcoR1 Capital, in rounds we track. Grouped by kind, each ranked by how many startups it shares with EcoR1 Capital. Rebuilt nightly; updated 15 November 2026. ## More portfolio maps [All portfolios](https://millionrounds.com/portfolio-maps) [Sector portfolio **EcoR1 Capital's Biotech portfolio** 16 startups ยท $3.7B](https://millionrounds.com/portfolio-maps/ecor1-capital-biotech-portfolio)[Co-investors **Who invests with Gaingels** 610 co-investors](https://millionrounds.com/portfolio-maps/gaingels-co-investors)[Co-investors **Who invests with Goldman Sachs** 398 co-investors](https://millionrounds.com/portfolio-maps/goldman-sachs-co-investors)[Co-investors **Who invests with General Atlantic** 207 co-investors](https://millionrounds.com/portfolio-maps/general-atlantic-co-investors)[Co-investors **Who invests with Pioneer Fund** 197 co-investors](https://millionrounds.com/portfolio-maps/pioneer-fund-2-co-investors)[Co-investors **Who invests with T. Rowe Price** 174 co-investors](https://millionrounds.com/portfolio-maps/t-rowe-price-co-investors) ## Raising from investors like EcoR1 Capital? Find the investors who back startups like yours, with their cheques, rounds and partners, in the app with filters, lists and exports. [Find investors](https://millionrounds.com/login?join=1&next=/app/investors)[Market maps](https://millionrounds.com/market-maps)