# Who Invests With Castle Island Ventures: 37 Co-Investors (2026) > The 37 investors that have backed two or more of the same startups as Castle Island Ventures, by kind: vc firms and private equity and asset managers. Source: https://millionrounds.com/portfolio-maps/castle-island-ventures-co-investors (Millionrounds; every figure on the page links to its filing or article) ## VC firms 34 - [Founders Fund](https://millionrounds.com/fund/founders-fund) - [Arca](https://millionrounds.com/fund/arca) - [Andreessen Horowitz](https://millionrounds.com/fund/andreessen-horowitz) - [Archetype](https://millionrounds.com/fund/archetype) - [Polychain](https://millionrounds.com/fund/polychain) - [CMT Digital](https://millionrounds.com/fund/cmt-digital) - [ParaFi Capital](https://millionrounds.com/fund/parafi) - [Craft Ventures](https://millionrounds.com/fund/craft-ventures) - [Goodwater Capital](https://millionrounds.com/fund/goodwater-capital) - [Amber Group](https://millionrounds.com/fund/amber-group) - [Hack VC](https://millionrounds.com/fund/hack-vc) - [Kleiner Perkins](https://millionrounds.com/fund/kleiner-perkins) - [Alumni Ventures](https://millionrounds.com/fund/us-strategic-tech-fund-an-alumni-ventures-fund) - [Digital Currency Group](https://millionrounds.com/fund/digital-currency-group) - [Maven 11 Capital](https://millionrounds.com/fund/maven-11) - [QED Investors](https://millionrounds.com/fund/qed-investors) - [Switch Ventures](https://millionrounds.com/fund/switch-ventures) - [Blockchain Founders Fund](https://millionrounds.com/fund/blockchain-founders-fund) - [Notation Capital](https://millionrounds.com/fund/notation-capital) - [First Round Capital](https://millionrounds.com/fund/first-round-capital) - [Founder Collective](https://millionrounds.com/fund/founder-collective) - [Haun Ventures](https://millionrounds.com/fund/haun-ventures) - [General Catalyst](https://millionrounds.com/fund/general-catalyst) - [Naval Ravikant](https://millionrounds.com/fund/naval-ravikant) +10 more ## Private equity and asset managers 3 - [Franklin Templeton](https://millionrounds.com/fund/franklin-templeton) - [Gaingels](https://millionrounds.com/fund/gaingels) - [Apollo](https://millionrounds.com/fund/apollo-global-management) ## Segment by segment ### VC firms 34 investors - [**Founders Fund**](https://millionrounds.com/fund/founders-fund) VC firm United States 4 backed - [**Arca**](https://millionrounds.com/fund/arca) VC firm United States 4 backed - [**Andreessen Horowitz**](https://millionrounds.com/fund/andreessen-horowitz) VC firm United States 4 backed - [**Archetype**](https://millionrounds.com/fund/archetype) VC firm United States 4 backed - [**Polychain**](https://millionrounds.com/fund/polychain) VC firm United States 4 backed - [**CMT Digital**](https://millionrounds.com/fund/cmt-digital) VC firm United States 4 backed - [**ParaFi Capital**](https://millionrounds.com/fund/parafi) VC firm United States 4 backed - [**Craft Ventures**](https://millionrounds.com/fund/craft-ventures) VC firm United States 3 backed ### Private equity and asset managers 3 investors - [**Franklin Templeton**](https://millionrounds.com/fund/franklin-templeton) Private equity United States 2 backed - [**Gaingels**](https://millionrounds.com/fund/gaingels) Private equity United States 2 backed - [**Apollo**](https://millionrounds.com/fund/apollo-global-management) Private equity United States 2 backed **How this map is made.** Every investor here has backed two or more of the same startups as Castle Island Ventures, in rounds we track. Grouped by kind, each ranked by how many startups it shares with Castle Island Ventures. Rebuilt nightly; updated 15 November 2026. ## More portfolio maps [All portfolios](https://millionrounds.com/portfolio-maps) [Portfolio map **Castle Island Ventures portfolio map** 46 startups · $1.9B](https://millionrounds.com/portfolio-maps/castle-island-ventures-portfolio-map)[Sector portfolio **Castle Island Ventures' Web3 & Crypto portfolio** 26 startups · $450M](https://millionrounds.com/portfolio-maps/castle-island-ventures-web3-crypto-portfolio)[Co-investors **Who invests with Techstars** 991 co-investors](https://millionrounds.com/portfolio-maps/techstars-co-investors)[Co-investors **Who invests with SV Angel** 988 co-investors](https://millionrounds.com/portfolio-maps/sv-angel-co-investors)[Co-investors **Who invests with Andreessen Horowitz** 977 co-investors](https://millionrounds.com/portfolio-maps/andreessen-horowitz-co-investors)[Co-investors **Who invests with Alumni Ventures** 911 co-investors](https://millionrounds.com/portfolio-maps/us-strategic-tech-fund-an-alumni-ventures-fund-co-investors) ## Raising from investors like Castle Island Ventures? 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)