Castle Island Ventures — Full Portfolio

Sealance builds The Sealance Trust Platform, a compliance and identity-verification system that uses zero-knowledge proofs and applied cryptography to enable privacy while enforcing regulatory compliance for the cryptocurrency industry.

AI & Machine LearningCrypto & Web3CybersecurityFintech

Shlomit Azgad-Tromer(Co-founder)Matthew Green(Co-founder)Eran Tromer(Co-founder)

Co-investorsFireblocksRibbit CapitalCoinbase VenturesDigital Currency GroupJump Capital

XFX operates a liquidity layer that provides unified fiat and stablecoin liquidity with intelligent routing and near-instant settlement, letting institutions trade across fiat and stablecoin pairs without pre-positioning capital.

Crypto & Web3Data & InfrastructureFintechMiami, US

Santiago Alvarado(Co-founder & CEO)

Co-investorsHaun VenturesOak HC/FTCoinbase VenturesMAYA CapitalMAYA Capital Ventures

Coin Metrics provides market and on-chain data, reference rates, and indexes for crypto and digital assets, delivered to institutional investment teams via APIs.

Crypto & Web3Data & InfrastructureFintechBoston, US

Timothy Rice(Executive Officer, Director)Tim Rice(Founder)in

BoardMathew S. McDermott(Director)Sean Judge(Director)inMatt Scott Walsh(Director)in

Board seatNic Carter· per SEC Form D · $6.7M raise · filed Oct 2023

Co-investorsAcrew CapitalCoinbase VenturesCollab+CurrencyCommunitas Capital PartnersDigital Currency GroupDragonfly+2 more

Miami, US

Board seatSean Judge· per SEC Form D · $20M raise · filed Jul 2026

Parry integrates software, hardware, and autonomy at the edge to turn complex technologies into mission-ready systems for contested defense environments.

Deep TechDefense TechRoboticsAlexandria, 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

Co-investorsTeamworthy Ventures

Surus is a financial infrastructure platform offering qualified custody, reserve management, and token issuance for digital asset builders, backed by its own North Carolina-chartered trust company.

Crypto & Web3Data & InfrastructureFintechWashington, US

Bradley Gibson(Chief Technology Officer)inBethany Wheeler(Chief Trust Officer)inJennifer Hoopes(Chief Legal Officer)inRachel Trujillo(Chief Compliance Officer)inPatrick Murck(Executive Officer, Director)in

Board seatNic Carter· per SEC Form D · $10.6M raise · filed Mar 2025

Co-investorsFinancial Venture StudioProtagonistRestive Ventures

A DeFi protocol creating a marketplace for blockspace.

Co-investorsCoinbase Ventures1kxCircle VenturesDragonflyRobot VenturesTribe Capital

Alpen Labs builds a Bitcoin layer-2 network that enables financial applications through a ZK rollup with optimistic bridge architecture.

Crypto & Web3FintechNew York City, US

Abishkar Chhetri(Founder)Pramod Kandel(Founder)Simanta Gautam(Founder)John LightTrey Del BonisLiam Eagen

Co-investorsHivemind Ventures, LlcLaunchpad CapitalMirana VenturesResolute VenturesSTILLMARKAsymmetric+3 more

Andrena is a wireless Internet service provider that delivers high-speed connectivity to multi-tenant buildings and households using wireless technology beamed to building roofs, then distributed wirelessly to units.

CleantechCloud ComputingNew Jersey, US

Neil Chatterjee(Founder)James Smits(Founder)in

Co-investors645 VenturesAfore CapitalBollinger Investment GroupCalm VenturesChaos VenturesChapter One+7 more

Co-investorsArrington CapitalLemniscapPantera CapitalArrington XRP Capital

Tools offering users secure financing against their cryptocurrency holdings.

Arch Lending (legal entity ChainFi, Inc) offers crypto-backed loans to U.S. borrowers and businesses, using digital assets as collateral.

Crypto & Web3FintechNew York, US

Dhruv Patel(Founder)inHimanshu Sahay(Founder)in

Co-investorsFormus CapitalFour Acres CapitalPICUS CAPITAL

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)inÁlvaro Correa Gallardo(Founder)

Co-investorsFounders FundSequoia CapitalY Combinator

Arx develops secure chips that embed blockchain authentication into physical items like apparel, collectibles, and certificates, enabling decentralized provenance verification and digital experiences without centralized servers.

Crypto & Web3Deep TechHardware

Co-investorsInflection.xyzPlaceholder VC1kxPlaceholderSeed Club Ventures

Asymmetry Finance is a decentralized finance protocol that lets users borrow stablecoins (USDaf and AmpUSD) against BTC or stablecoin collateral at customizable fixed interest rates.

Crypto & Web3Fintech

Co-investorsF-Prime CapitalMagnus CapitalSilvermine CapitalAvon VenturesEcco Capitalgmjp+1 more

Delivers decision-grade intelligence on U.S. banks by integrating regulatory filings, securities data, and property deed information.

Atrium is an AI-powered analytics platform that unifies bank filings, real estate lending data, county records, and earnings-call transcripts to provide loan-level intelligence for credit due diligence, CRE and multifamily portfolio exposure analysis, and risk assessment.

AI & Machine LearningData & InfrastructureFintech

Attestiv offers an AI-powered platform that validates digital files—photos, videos, audio, and documents—to detect tampering, deepfakes, and fraud using rules-based and machine learning models, delivered via a dashboard, APIs, and SDKs.

AI & Machine LearningCybersecurityInsurTechLehi, US

Nicos Andrew Vekiarides(Executive Officer, Director)John Whitney Bates(Executive Officer, Director)Nicos VekiaridesinJohn BatesinThomas Mark Morley(Executive Officer)Emmanuel Parasirakis(Executive Officer)

Co-investorsBorderless VenturePlug and Play Ventures

Babylon Labs develops trustless infrastructure that enables Bitcoin to be used as collateral in decentralized finance and through a Bitcoin staking protocol for blockchain validation.

Crypto & Web3

Fisher Yu(Founder)

Co-investorsa16z cryptoAlumni VenturesAndreessen HorowitzBasecamp FundHack VCIOSG Ventures+3 more

A global payments network enabling consumers and businesses to transact in any currency, anywhere on earth.

Bitwise offers professionally managed crypto investment funds and products, including ETFs, separately managed accounts, private funds, and staking.

Crypto & Web3FintechSan Francisco, US

Hong Kim(Executive Officer, Director)Hunter Horsley(Founder & CEO)inKatherine Dowling(Executive Officer)Matt Hougan(Executive Officer)Teddy Fusaro(Executive Officer)

BoardCorey Mulloy(Director)

Co-investorsBlockchain CapitalChorus OneCoinbase VenturesCraft VenturesDria VenturesElectric Capital+5 more

Coala Pay provides a settlement layer and payment infrastructure for humanitarian and development aid programs, handling institutional grants, household cash transfers, frontline worker payments, and vendor settlements.

Crypto & Web3FintechImpact & Social Good

Co-investorsCV VCLattice CapitalReflexive CapitalCommerce VenturesFactor Capital

Eaglebrook is a crypto investment platform for wealth managers, offering tax-optimized Bitcoin, Ethereum, and multi-asset separately managed accounts (SMAs) held in segregated accounts at qualified custodians.

Crypto & Web3FintechSaaS

Christopher King(Founder)in

Co-investorsBrewer Lane VenturesF-Prime CapitalAvon VenturesFranklin TempletonGemini Frontier FundJump Capital

Erebor is a US national bank in Columbus, Ohio serving AI, crypto, defense and advanced manufacturing companies.

Palmer Luckey(Founder)

Co-investorsAntiArctic DigitalBalerion Space VenturesIneffable VenturesLakeside CapitalLux Capital+5 more

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 MarketplacesFintechSan Francisco, US

Bernardo Garcia(Founder)

Co-investorsContour Venture PartnersDorm RoomHTwentyMONASHEESQED InvestorsSwitch Ventures+4 more

Groma issues GromaCoin, a blockchain token where each coin is a tokenized share in the Groma Real Estate Trust, backed by income-producing US real estate held in a regulated structure.

Crypto & Web3FintechPropTech

Chris Lehman(Founder)Grant Fishman(Founder)in

Co-investorsBantam GroupCoinbase VenturesLaunchpad Venture Group

Hoseki provides cryptographic verification of Bitcoin and digital asset holdings, letting holders generate verifiable proofs of ownership and businesses request and verify counterparty holdings without exposing addresses or sensitive data.

Crypto & Web3FintechSaaS

Sam Abbassi(CEO)Cory Wilbur(CTO and Head of Product)in

Co-investorsF-Prime CapitalFulgur VenturesSTILLMARKAvon VenturesTen31

Kintsu is a liquid staking protocol on the Monad blockchain that lets users stake MON tokens and receive sMON liquid staking tokens usable across DeFi for trading, lending, and pooling while earning staking and MEV yield.

Crypto & Web3Fintech

Connor McKenzie(Founder)in

Co-investorsNxGenPragma VenturesReciprocal VenturesBrevan Howard Digital

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 & Web3Developer ToolsEnterprise SoftwareFintechSaaSSan Francisco, US

Matt Marcus(Co-Founder & CEO)inDimitri Dadiomov(Cofounder & CEO)inSam Aarons(Co-Founder & CTO)in

Co-investorsArchetypeArtisanal VenturesCleo CapitalMischiefNewView CapitalQuiet Capital+7 more

Nirvana Labs operates a high-performance cloud platform offering bare metal compute, accelerated block storage, private networking, and managed Kubernetes orchestration for latency-sensitive, data-heavy systems.

Cloud ComputingData & InfrastructureEnterprise Software

Co-investorsCrucible CapitalHash3 CapitalLattice CapitalRaptor GroupJump CryptoRW3 Ventures

Project Eleven builds post-quantum cryptography and migration tooling for Bitcoin, Ethereum and other digital asset networks.

Co-investorsCoinbase VenturesLattice CapitalQuantonationVariant FundBalaji SrinivasanFin Capital+1 more

PYOR provides blockchain data analytics for crypto protocols, DAOs, and institutional investors, offering custom dashboards, risk and governance insights, and developer tools.

Crypto & Web3Data & InfrastructureDeveloper Tools

Co-investorsFuture Perfect VenturesHash3 CapitalAntlerCoinbase VenturesForce Ventures

Ripple builds blockchain-based financial infrastructure to enable cross-border value transfer and payment solutions for enterprises, governments, and financial institutions.

Crypto & Web3Enterprise SoftwareFintechSan Francisco, US

Ryan Fugger(Founder)David Schwartz(Director)inSusan Athey(Director)Gene Sperling(Director)Christian Larsen(Executive Officer, Director, Promoter)Young Guo(Director)

Co-investors500 GlobalAbstract VenturesAurum Venture PartnersAvant Global LLCCamp One VenturesCore Venture Capital+19 more

Station70 builds institutional-grade security products for enterprise asset protection, including private key backup and recovery (Bunker) and secrets management (Gatekeeper).

Crypto & Web3CybersecurityEnterprise SoftwareConcord, US

Adam Healy(Founder)inAdam Everspaugh(Founder)Dr Adam Everspaugh(Founder)

Co-investorsA100X VenturesMetalayerSCB 10XNotation CapitalSemantic Ventures

Talos provides white-label cryptocurrency trading infrastructure and technology for retail investment platforms and digital asset brokerages.

Crypto & Web3Data & InfrastructureFintechSaaS

Anton Katz(Founder & CEO)in

Co-investors10SQ Capital (TenSquared)a16z cryptoAndreessen HorowitzCoinbase VenturesElefundFin Capital+12 more

Tesser provides stablecoin payment infrastructure for financial institutions, including global stablecoin settlement, off-ramp-as-a-service, and stablecoin payment capabilities with wallet infrastructure, on/off ramps, and compliance tools.

Crypto & Web3Enterprise SoftwareFintechNew York City, US

Geetha Panchapakesan(Founder)in

Co-investorsDigital Currency GroupStrobe Ventures

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)

Co-investorsAlumni VenturesB Capital GroupB4 CapitalBasecamp FundBessemer Venture PartnersGeodesic Capital+12 more

Valinor Discovery generates patient-derived datasets combining multi-omics and clinical data to enable machine learning applications in drug development.

AI & Machine LearningBiotechMedical Devices

Co-investorsCampus Founders FundMythos Ventures Management, LlcMaven 11

Valinor is a credit institution building infrastructure for "Open Credit," aiming to connect traditional credit markets with onchain finance.

Crypto & Web3FintechNew York, US

Lily Yarborough(Executive Officer, Director, Promoter)inConnor Dougherty(Executive Officer, Director, Promoter)in

BoardSean Judge(Director)Nazar Khan(Director)

Co-investorsDepartment of XYZMaven 11Venture Dept.

Yellow Card provides digital asset and fiat payments infrastructure that lets banks, financial institutions, corporates, and other businesses access, store, send, and manage stablecoins and make payments across USD and 50+ local currencies.

Chris Maurice(Founder)inJustin Poiroux(Founder)in

Co-investorsAtlanta Technology AngelsDG Daiwa VenturesFenbushi CapitalPharsalus CapitalSony Ventures CorporationSozo Ventures+1 more

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)Pat Larsen(Co-Founder / CEO)Daniel Escobar(Chief Technology Officer)

BoardMark Casady(Director)in

Co-investorsBloccelerate VCBorderless VentureConvergeKing River CapitalOssian CapitalParaFi Capital+7 more