FFundraiseJet
Castle Island Ventures logo

Castle Island Ventures

Cambridge, Massachusetts · Invests in US · Website

Check size

$100K-$5M

+ Save to my list

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

MW

Matthew Walsh

Founding Partner · Primary contact

NC

Nic Carter

Founding Partner

SJ

Sean Judge

General Partner

RB

Ria Bhutoria

General Partner

RS

Rich Sgalardi

General Partner

GM

Gretchen McCarey

Chief Financial Officer

GC

Gus Coldebella

Chief Legal Officer

WK

Wyatt Khosrowshahi

Investor

HH

Henry Harris

Investor

HM

Hunter Merghart

Venture Partner

Portfolio

Erebor BankFintech Payments
AlkimiyaFintech Payments

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 LabsFintech Payments

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.

AndrenaEnterprise Software

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.

ArcadeMarketing Adtech

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 LendingFintech Payments

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

Asymmetry FinanceFintech Payments

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.

AtriumManufacturing Industrial

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.

AttestivSecurity Cyber

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 LabsFintech Payments

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

BeamEnterprise Software

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 ElevenSecurity Cyber

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

Castle Island Ventures in the news

Similar firms

CMS Holdings$500K–$10M

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.

Blockchain Capital$25K–$200K

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.

Pantera Capital$100K–$5M

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.

Polychain$1M–$50M

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.

Scalar Capital$100K–$5M

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.

Research briefRead more
Castle Island Ventures Research Investment Thesis Castle Island Ventures is a specialized venture capital firm exclusively focused on public blockchains and cryptoassets. Founded in 2018 by Fidelity alums Nic Carter and Matt Walsh, the firm partners with entrepreneurs building transformative companies powered by public blockchain technologies. The firm believes that public blockchains represent a paradigm shift in how we interact with money, financial services, and the internet itself. Core Investment Themes Castle Island invests across three major themes: Monetary Networks : The firm sees an ongoing monetary transition towards rules-based monetary systems. This includes infrastructure on both non-sovereign networks like Bitcoin and Ethereum, as well as the rapid emergence of stablecoins that give savers worldwide free choice of currency. Their extensive research on stablecoins as emerging market infrastructure demonstrates deep conviction in this thesis. Financial Services Infrastructure : Castle Island envisions a financial system that is more programmable, transparent, less politicized, and less intermediated. They support companies building DeFi protocols, financial market infrastructure, and lending solutions that disrupt legacy financial services. They explicitly note that traditional financial services firms failing to evolve will face disruption similar to what happened to newspapers with the web. Internet Architecture (Web3) : In parallel with monetary and financial transformation, the firm believes decentralized internet topologies will prove commercially superior to centralized models. They support projects restoring digital property rights, enabling new business models, and disrupting data monopolies. Portfolio & Recent Activity As of January 2026, Castle Island has invested in 76+ companies with 9 new investments in the last 12 months. Notable recent activity includes: January 2026: Led $20M Series A in Project Eleven (quantum-resistant digital asset infrastructure) at $120M valuation January 2026: Invested in Chakra (database software for blockchain) December 2025: Invested in Sova September 2025: Led $2.8M pre-seed in RockSolid (liquid staking/vaults) Portfolio includes unicorns: Talos, Crusoe Energy, MoonPay. Early investor in BlockFi, Bitwise, River Financial with successful track records. Fund History & Assets Under Management Castle Island has raised three funds: Fund I: Early fund establishing blockchain thesis Fund II: $50M (announced 2019-2020) Fund III: $250M (announced February 2022, currently actively deploying) Current AUM of approximately $250M+ is actively deployed in early-stage public blockchain companies. The fund has a diversified LP base including endowments, foundations, asset managers, insurers, family offices, and fund-of-funds. Team & Leadership The firm is led by four General Partners with complementary expertise: Nic Carter (Founding Partner): Former Fidelity cryptoasset analyst and Coin Metrics cofounder. Carter is known as a thought leader on blockchain policy and brings deep understanding of monetary systems and stablecoins. Matthew Walsh (Founding Partner): Led Fidelity's blockchain and cryptoasset initiatives before founding Castle Island. Walsh brings institutional finance experience and board-level governance expertise. Sean Judge (General Partner): Former Principal at Highland Capital Partners. Focus on financial market infrastructure, consumer fintech, and new blockchain applications. Economics background from Vanderbilt. Ria Bhutoria (General Partner, recently promoted): Former Director of Research at Fidelity Digital Assets and Senior Research Analyst at Circle. Brings deep expertise in Bitcoin, digital assets, and research infrastructure. Additional team includes Richard Sgalardi (General Partner, crypto trading background), plus investors and venture partners with expertise in blockchain infrastructure, fintech, and institutional finance. Investment Strategy & Approach Stage Focus : Primarily Seed and Series A, with selective pre-seed and later-stage participation Check Size : $100K to $5M typical range, with capacity for larger allocations and reserves for follow-ons Decision Making : Partnership model where individual partners have meaningful investment authority, enabling fast decision-making Founder Preferences : Technical founders with blockchain/cryptoasset expertise, shipping experience, regulatory understanding, and mission-driven approaches Typical Involvement : Board seats, active partnerships, and ongoing operational support Sector & Thesis Preferences Castle Island's exclusive focus on public blockchains means they invest in: Bitcoin infrastructure and applications Ethereum and EVM-compatible chain innovations Layer 2 solutions and rollup technology Stablecoins and monetary infrastructure DeFi protocols and financial primitives Blockchain scaling and performance Bitcoin restaking and security solutions Enterprise blockchain applications They explicitly avoid gambling/casino games, speculative-only assets, and proof-of-work mining operations. Thought Leadership & Content Castle Island is highly active in thought leadership: "On the Brink" podcast with 680+ episodes exploring blockchain and crypto topics Regular research whitepapers (e.g., "Stablecoin Payments from the Ground Up" - June 2025) Published perspectives on emerging markets, Bitcoin security, stablecoins, and regulation Monthly newsletter with market insights Strong voices: Nic Carter particularly influential in blockchain policy discussions Portfolio Companies (Representative Sample) Alkimiya, Alpen Labs, Andrena, Arcade, Arch, Asymmetry Finance, Atrium, Attestiv, Babylon Labs, Beam, BlockFi, Bitwise, River Financial, Talos, Crusoe Energy, MoonPay, Project Eleven, RockSolid, and 58+ additional companies Market Position Castle Island Ventures holds the position of one of the earliest and most respected blockchain-focused venture capital firms. The combination of Fidelity heritage, technical depth, thoughtful thesis, and active engagement with entrepreneurs and policy makers makes them a leading voice in blockchain investment and governance.

Add Castle Island Ventures to your investor list

Sign up free to save investors, see partner contacts, and track your raise.

Sign up