Castle Island Ventures
Cambridge, Massachusetts · Invests in US · Website
Check size
$100K-$5M
Thesis
Public blockchains represent a paradigm shift in how we interact with money, financial services, and the internet. We invest in infrastructure and application companies building the future of monetary networks, programmable finance, and decentralized internet architecture.
Likely not a fit for
We do not invest in gambling/casino games, speculative-only assets, or proof-of-work mining operations. We focus exclusively on public blockchains.
How they invest
- Lead or follow
- Usually leads
- Typical decision
- ~1 week
- Warm intro
- Not required
- Involvement
- Takes a board seat
- Fund status
- Actively deploying
- Assets under mgmt
- $250M
- Decision process
- Partnership vote
Partners & team
10 contacts on file
Matthew Walsh
Founding Partner · Primary contact
Nic Carter
Founding Partner
Sean Judge
General Partner
Ria Bhutoria
General Partner
Rich Sgalardi
General Partner
Gretchen McCarey
Chief Financial Officer
Gus Coldebella
Chief Legal Officer
Wyatt Khosrowshahi
Investor
Henry Harris
Investor
Hunter Merghart
Venture Partner
Portfolio
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.
Beam is a company that offers a comprehensive platform for construction project management, integrating tools for estimating, project management, and financial management. Their software is designed to help contractors streamline operations, improve profitability, and enhance overall project organization.
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.
Recent activity
- Feb 2026
Erebor Bank
Series A · Participated
- Jan 2026
Project Eleven
Series A · Lead
- Jan 2026
Chakra
Seed · Participated
- Dec 2025
Sova
Seed · Participated
- Sep 2025
RockSolid
Pre-Seed · Lead
Castle Island Ventures in the news
CryptoRank
GPT Ventures - Investment Fund Review
8 days ago
Fortune
Ex–Blackstone staffers raise $25 million for startup Valinor, which aims to put private credit on the blockchain
3 months ago
Axios
Rebellions snares $400m, Qodo's coding bet, and Nxtra's $1b
3 months ago
Fortune
Exclusive: Foreign exchange startup XFX raises $17 million to help businesses go between cash and stablecoins
3 months ago
Fortune
Exclusive: Cyclops raises $8 million to build stablecoin infrastructure for payments companies
4 months ago
The Block
Stablecoin payments startup Cyclops raises $8 million from Castle Island Ventures, F-Prime and Shift4
4 months ago
CoinDesk
Post-quantum crypto startup Project Eleven raises $20 million in funding round
6 months ago
Quantum Computing Report
Project Eleven Secures $20 Million Series A to Protect Digital Assets from Quantum Threats
6 months ago
PR Newswire
Project Eleven Raises $20M to Prepare Digital Asset Infrastructure for the Quantum Era
6 months ago
The Block
Project Eleven raises $20 million Series A at $120 million valuation to prepare crypto networks for post-quantum threats
6 months ago
The Block
Castle Island Ventures leads $2.8 million pre-seed round for liquid vault startup RockSolid
10 months ago
CoinDesk
Nic Carter’s Castle Island Ventures Raises $250M for Third Crypto Fund
Feb 2022
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Research briefRead more
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