Castle Island Ventures is a venture capital fund founded by former Fidelity executives who helped build the asset manager's early crypto efforts before spinning out to focus exclusively on equity investments in companies building on public blockchains like Bitcoin, deliberately avoiding token trading to minimize regulatory risk. The firm operates as both an early-stage investor writing $250k-$1m checks and a research hub through their podcast and stablecoin reports, positioning themselves as a bridge between crypto builders and large financial institutions like banks and ETF issuers.