Castle Island Ventures

Alkimiya is a market protocol for trading blockspace and fundamental metrics. It offers predictive markets and total supply forecasts for USDC, allowing users to manage and monitor their open orders.

Alpen Labs is building Bitcoin's future by enabling direct programmability of Bitcoin through zero-knowledge proofs, facilitating secure trading, borrowing, and the creation of financial applications on the Bitcoin network.

Andrena provides high-speed Internet services starting at $30 per month, focusing on affordability and simplicity for residents and businesses. Their service includes plans up to 1 Gbps with no hidden fees and quick setup.

Arcade is a platform that enables users to create interactive product demos and storytelling experiences quickly and easily. With features like a Creator Studio for on-brand visuals and personalization tools, Arcade helps businesses enhance their marketing and sales efforts through engaging product narratives.

Arch Lending provides secure and instant Bitcoin and crypto-backed loans, allowing users to unlock liquidity without selling their digital assets.

Asymmetry Finance is focused on providing innovative financial products such as stablecoins and structured products for liquid staking and restaking, aiming to supercharge yield sustainably.

Atrium Windows & Doors is a leading manufacturer of high-quality vinyl windows and patio doors, committed to providing exceptional products and customer service since 1946.

Attestiv provides a cloud-scale platform to ensure the authenticity and validity of digital assets utilizing patented AI technology, addressing the challenges of fake and AI-generated media.

Babylon Labs focuses on Bitcoin staking and decentralized finance (DeFi) solutions, providing institutional staking services and developing protocols for enhancing Bitcoin's utility.

Project Eleven is an applied lab of builders and technologists at the intersection of quantum computing and cryptography, focusing on securing digital assets for the post-quantum era.

Partner-owned venture capital fund with no outside investors that takes faster, higher-risk crypto positions including yield farming and NFTs. Combines ex-Circle Trade founders' trading expertise with venture investing, offering trader reflexes with a venture time horizon.

Longstanding crypto track record and relationships, plus a pioneering tokenized, tradable LP structure that pays on-chain dividends via security tokens. Founded in 2013 by brothers Bart and Brad Stephens as one of the first dedicated crypto venture funds.

First U.S. institutional asset manager focused exclusively on blockchain. Launched the first U.S. bitcoin fund in 2013 and operates a full-spectrum model investing across venture equity, private tokens, liquid tokens, and special situations with a single investment committee.

Invests in pre-launch and long-horizon base-layer networks, combining hedge-fund–style liquid token trading with venture investing while actively managing on-chain positions and providing hands-on protocol governance. Founded by Coinbase's first employee, the fund runs a hybrid structure that actively manages on-chain positions while backing pre-launch networks, focusing on owning and governing base-layer networks and economic primitives.

Co-founded by ex-Coinbase employees, Scalar Capital specializes in privacy and censorship-resistant protocols. The fund operates more like a crypto research shop than a typical investment firm, running technical conferences with top cryptographers and maintaining deep involvement in DAO governance across multiple ecosystems. Partners personally create widely-cited technical content and educational materials used by founders and developers.