Castle Island Ventures
Venture capitalActively deployingBoston · Pre-Seed–Series A · 12 people tracked
Also known as CASTLE ISLAND MANAGEMENT, LLC
Investment thesis
Castle Island Ventures invests exclusively in public blockchain technologies, supporting entrepreneurs building the infrastructure and application companies needed to help these protocols reach their potential. The firm targets early-stage companies operating at the intersection of traditional finance and public blockchains, with a focus on accelerating frictionless finance.
Source: firm website, verified Aug 3, 2026.
Team · 12 people
from the firm's website
What they invest in
from 20 of 34 portfolio companiesCrypto & Web3 ×16Fintech ×13Enterprise Software ×5SaaS ×5Cybersecurity ×4AI & Machine Learning ×3Data & Infrastructure ×2B2B Marketplaces ×1
HQs:United States×10United Kingdom×1
Investments · 34 tracked
founders shown can be your intro pathCoin Metrics provides market and on-chain data, reference rates, and indexes for digital assets via APIs, serving institutional investment teams.
Crypto & Web3Data & InfrastructureFintechBoston, US
Mathew S. McDermott(Director)Sean Judge(Director)Matt Scott Walsh(Director)Timothy Rice(Executive Officer, Director)Nic Carter(Executive Officer, Director)Bob Davis(Director)
Board seatNic Carter· per SEC Form D · $6.7M raise · filed Oct 2023
Miami, US
Board seatSean Judge· per SEC Form D · $20M raise · filed Jul 2026
Alexandria, US
Jon Pilon(Executive Officer)Aydin Mohtashamian(Executive Officer)John D Parkes(Executive Officer, Director)
BoardRobert Miller(Director)David Gross(Director)
Board seatGus Coldebella· per SEC Form D · $90.7M raise · filed Nov 2024
Surus provides infrastructure combining blockchain, financial services, and securities expertise, operating a trust company (Surus Trust Company).
Crypto & Web3FintechWashington, US
Brad Gibson(Director)Patrick Murck(Executive Officer, Director)Bradley Gibson(Chief Technology Officer)Bethany Wheeler(Chief Trust Officer)Jennifer Hoopes(Chief Legal Officer)Rachel Trujillo(Chief Compliance Officer)
Board seatNic Carter· per SEC Form D · $10.6M raise · filed Mar 2025
A DeFi protocol creating a marketplace for blockspace.
Alpen Labs builds a Bitcoin layer-2 network that enables financial applications through a ZK rollup with optimistic bridge architecture.
Crypto & Web3Fintech
John LightTrey Del BonisLiam EagenManish BistaAaron Feickert
Tools offering users secure financing against their cryptocurrency holdings.
ARQ Finance (formerly DolarApp) is a digital financial platform that enables currency exchange to digital dollars and euros, international payments, and investment access to global markets.
Crypto & Web3FintechLondon, GB
Fernando Terrés(CEO and co-founder)inZach Garman(Founder)inAlvaro Correa(Founder)in
Delivers decision-grade intelligence on U.S. banks by integrating regulatory filings, securities data, and property deed information.
Attestiv operates a cloud-based SaaS platform that uses patented AI to analyze and score photos, videos, and documents for authenticity, detecting fakes, alterations, and generative AI-created media.
AI & Machine LearningCybersecurityInsurTech
Matthew Walsh(Director)Nicos Andrew Vekiarides(Executive Officer, Director)John Whitney Bates(Executive Officer, Director)Thomas Mark Morley(Executive Officer)Emmanuel Parasirakis(Executive Officer)Jason Weiss(Director)
A global payments network enabling consumers and businesses to transact in any currency, anywhere on earth.
Bitwise Investments provides professionally managed cryptocurrency funds and investment products for institutional and individual investors.
Crypto & Web3FintechSan Francisco, US
Katherine Dowling(Executive Officer)Matt Hougan(Executive Officer)Teddy Fusaro(Executive Officer)Corey Mulloy(Director)Hong Kim(Executive Officer, Director)Hunter Horsley(Founder & CEO)
Felix is a remittance service that enables users to send money from the United States to Latin America (Mexico, Guatemala, Honduras, El Salvador, and Dominican Republic) via WhatsApp, with funds delivered to bank accounts, mobile wallets, or cash pickup locations.
B2B MarketplacesFintech
Modern Treasury provides a payments infrastructure platform that enables businesses to move and track money across fiat and stablecoin rails through a single API.
Crypto & Web3Enterprise SoftwareFintechSaaSSan Francisco, US
Matt Marcus(Co-Founder & CEO)inDimitri Dadiomov(Cofounder & CEO)inSam Aarons(Co-Founder & CTO)in
Station70 builds institutional-grade security products for enterprise asset protection, including private key backup and recovery (Bunker) and secrets management (Gatekeeper).
Crypto & Web3CybersecurityEnterprise Software
TRM Labs offers an online certification course on blockchain investigations and crypto forensics for professionals who need to trace cryptocurrency transactions across multiple blockchains.
AI & Machine LearningCrypto & Web3CybersecurityEdTechEnterprise SoftwareFintechGovTechSan Francisco, US
Esteban Castaño(Founder)inRahul Raina(Founder)inSujit Raman(Chief Legal Officer)Ari Redbord(Global Head of Policy)Tom Armstrong(Head of Compliance Advisory)
Valinor Discovery generates patient-derived datasets combining multi-omics and clinical data to enable machine learning applications in drug development.
AI & Machine LearningBiotechMedical Devices
XFX is a liquidity layer that enables institutions to move money across fiat and stablecoin pairs with intelligent routing, instant settlement, and no required capital pre-positioning.
Crypto & Web3FintechSaaS
ZenLedger provides tax and accounting software that automates cryptocurrency tax calculations for crypto traders, investors, and tax professionals.
Crypto & Web3FintechSaaSSeattle, US
Patrick Larsen(Founder & CEO)Mark Casady(Director)Pat Larsen(Co-Founder / CEO)Daniel Escobar(Chief Technology Officer)
Rows marked “SEC filing” are inferred from directors named on the company's SEC Form D — public regulatory data, not a portfolio list published by the firm.
Frequently asked questions
- What stage does Castle Island Ventures invest at?
- Castle Island Ventures invests at the Pre-Seed, Seed, Series A stages.
- What is Castle Island Ventures's typical check size?
- Castle Island Ventures typically writes checks of $100K – $5M.
- What sectors does Castle Island Ventures focus on?
- Castle Island Ventures focuses on Crypto & Web3, Cybersecurity, Enterprise Software, Fintech.
- Where is Castle Island Ventures located?
- Castle Island Ventures is headquartered in Boston, US.
- Does Castle Island Ventures lead rounds?
- Yes, Castle Island Ventures leads investment rounds.
From the blog
visit blog ↗Castle Island Ventures publishes weekly roundups covering developments across crypto markets, including security vulnerabilities (Coldcard exploits, quantum risk), regulatory pressures (CLARITY Act, CBDC bans, SEC enforcement), and infrastructure changes (BitMEX shutdown, blockchain patent acquisitions, tokenized settlement pilots). AI summary
Media · Podcasts & interviews
featuring the teamRia Bhutoria, Castle Island Ventures | Boys Club Interview at Real-World Asset Summit 2023
Centrifuge · Ria Bhutoria
The Boston Blockchain Podcast EP 1 | Nic Carter And Matt Walsh On Starting Castle Island Ventures
Boston Blockchain Week · Nic Carter
Crypto confidence is 'shattered' with FTX's future in question, says Castle Island Ventures' Nic Carter
Nic Carter · cnbc.com
Luna's bitcoin liquidation marks significant reversal: Castle Island Ventures' Nic Carter
CNBC Television · Nic Carter
Ep 39 | DAOs, Stablecoins & The Long Case for Bitcoin with Nic Carter of Castle Island Ventures
The Money Movement with Jeremy Allaire · Nic Carter
Castle Island Ventures featuring Nic Carter and Matt Walsh, Founding Partners - BlockFi Live 🔴
BlockFi · Nic Carter
Images
Co-investors · 19
Pantera Capital is a blockchain and cryptocurrency-focused investment firm that pioneered early crypto funds in the U.S., offering exposure through venture equity, early-stage tokens, and liquid tokens.
Acrew Capital is a venture capital firm that emphasizes a team-based approach to investing, offering portfolio companies access to its full team.
Electric Capital is an early-stage venture firm founded in 2018 that backs founders building trust-minimized technologies across AI, crypto, fintech, and related sectors.
Hack VC is a thesis-driven venture capital firm that partners with founders at the earliest stages building next-generation Internet technologies across crypto, AI, and other frontier areas.
Stillmark is a venture capital firm that invests in companies building products and infrastructure for a bitcoin-powered future.
Red Swan Ventures backs founders at the earliest stage, aiming to be a founder's first outside capital, focusing on companies born from platform shifts and cultural insight that serve enduring human needs.
M13 is a venture capital firm that backs early-stage founders building companies through structural market shifts.
Initialized Capital is a venture capital firm that backs seed-stage founders across a wide range of sectors, providing hands-on guidance from company formation onward.
Cyberstarts is a venture firm focused on cybersecurity startups, backing founders who have overcome significant challenges and using a systematic process to identify urgent problems in the sector.
Highland Capital Partners is a venture capital firm with a 39-year history focused on backing entrepreneurs, reporting 200 exits, over 50 IPOs, 40 unicorns, and $7B in assets under management.
Polygon is a blockchain platform positioned as infrastructure for global payments and money movement, enabling assets to move onchain at scale. It offers an open stack for accessing the onchain economy and is powered by its native token $POL.
The Venture Collective (TVC) is a venture capital firm that invests in and supports a portfolio of startups across sectors such as energy and consumer products.
▶7 more co-investors
Solana VenturesShima CapitalAirTree VenturesChampion Hill VenturesBlockchain Founders FundCadenzaLakehouse Venture Partners
Firms observed investing alongside Castle Island Ventures, from public investor directories. Shared companies are the overlap with Castle Island Ventures's recorded portfolio.
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