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

SAShlomit Azgad-Tromer(Co-founder)inMatthew Green(Co-founder)inEran Tromer(Co-founder)in

Co-investorsFIFireblocksRIRibbit CapitalCOCoinbase VenturesDIDigital Currency GroupJUJump 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

SASantiago Alvarado(Co-founder & CEO)in

Co-investorsHAHaun VenturesOAOak HC/FTCOCoinbase VenturesMAMAYA CapitalMAMAYA 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

TRTim Rice(Founder)in

BoardMathew S. McDermott(Director)SJSean Judge(Director)inMSMatt Scott Walsh(Director)inBob Davis(Director)in

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

Co-investorsACAcrew CapitalCOCoinbase VenturesCOCollab+CurrencyCOCommunitas Capital PartnersDIDigital Currency GroupDRDragonfly+3 more

Parry builds integrated mission systems combining software, hardware, and AI-enabled autonomy that operate across platforms and environments without requiring custom integration.

AI & Machine LearningDeep TechDefense TechEnterprise SoftwareRoboticsAlexandria, US

JPJon Pilon(Executive Officer)inAMAydin Mohtashamian(Executive Officer)inJohn D Parkes(Executive Officer, Director)in

BoardRobert Miller(Director)David Gross(Director)

Board seatGCGus Coldebella· per SEC Form D · $90.7M raise · filed Nov 2024

Co-investorsTETeamworthy 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

BGBradley Gibson(Chief Technology Officer)inBWBethany Wheeler(Chief Trust Officer)inJHJennifer Hoopes(Chief Legal Officer)inRTRachel Trujillo(Chief Compliance Officer)inPMPatrick Murck(Executive Officer, Director)in

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

Co-investorsFIFinancial Venture StudioPRProtagonistRERestive Ventures

A DeFi protocol creating a marketplace for blockspace.

Co-investorsCOCoinbase Ventures1K1kxCICircle VenturesDRDragonflyRORobot VenturesTRTribe 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

ACAbishkar Chhetri(Founder)inPKPramod Kandel(Founder)inSimanta Gautam(Founder)inJLJohn LightinTrey Del BonisLELiam Eagen

Co-investorsHIHivemind Ventures, LlcLALaunchpad CapitalMIMirana VenturesREResolute VenturesSTSTILLMARKASAsymmetric+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

NCNeil Chatterjee(Founder)inJSJames Smits(Founder)in

Co-investors64645 VenturesAFAfore CapitalBOBollinger Investment GroupCACalm VenturesCHChaos VenturesCHChapter One+7 more

Modern Treasury provides a payment infrastructure platform that enables companies to launch multi-rail payment products supporting both fiat and stablecoins through a single API.

Cloud ComputingCrypto & Web3Data & InfrastructureFintechSaaS

Co-investorsARArca FundsARArchetypeBLBlocktower CapitalENEniac VenturesSOSoma Capital

Arch operates an automated crypto lending platform that offers Bitcoin-backed loans, allowing investors to configure and receive funding within minutes.

Crypto & Web3FintechNew York, US

DPDhruv Patel(CEO & Co-founder)inHSHimanshu Sahay(CTO & Co-founder)in

Co-investorsFOFormus CapitalFOFour Acres CapitalPIPICUS 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

FTFernando Terrés(CEO and co-founder)inZGZach Garman(Founder)inACAlvaro Correa(Founder)inÁCÁlvaro Correa Gallardo(Founder)in

Co-investorsFOFounders FundSESequoia CapitalY Y 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-investorsINInflection.xyzPLPlaceholder VC1K1kxPLPlaceholderSESeed Club Ventures

ARx makes a hands-free wearable headset for people with low vision or sight loss, using a camera that streams video in real time to AI-powered visual assistance apps and bone-conduction audio to describe objects, text, and surroundings.

AI & Machine LearningHardwareHealthtech

Co-investors5L5Lion Ventures1K1kxPLPlaceholderSESeed 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-F-Prime CapitalMAMagnus CapitalSISilvermine CapitalAVAvon VenturesECEcco CapitalGMgmjp+1 more

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

NVNicos Vekiarides(Executive Officer, Director)inJohn Bates(Executive Officer, Director)inThomas Mark Morley(Executive Officer)Emmanuel Parasirakis(Executive Officer)in

BoardMWMatthew Walsh(Director)inJason Weiss(Director)in

Co-investorsBLBlockchain CoinvestorsBOBorderless VenturePLPlug 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 & Web3Fintech

Fisher Yu(Founder)in

Co-investorsA1a16z cryptoALAlumni VenturesANAndreessen HorowitzBABasecamp FundBLBloccelerate VCBRBreyer Capital+9 more

Birdai builds tools to measure, verify, and recover value lost between an order and its fill on onchain markets, using a single metric (β) to quantify execution quality.

Crypto & Web3Data & InfrastructureFintech

KFKevin FarrellyinGreg ScanloninJames McClain

Co-investorsDEDepartment of XYZMEMetalayerVEVenture Dept.

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

Crypto & Web3FintechSan Francisco, US

HKHong Kim(Executive Officer, Director)inHHHunter Horsley(Founder & CEO)inKDKatherine Dowling(Executive Officer)inMHMatt Hougan(Executive Officer)inTFTeddy Fusaro(Executive Officer)in

BoardCorey Mulloy(Director)

Co-investorsBLBlockchain CapitalCHChorus OneCOCoinbase VenturesCRCraft VenturesDRDria VenturesELElectric Capital+7 more

Casa provides self-custody solutions for bitcoin and stablecoins, offering multi-signature security infrastructure for both individual and institutional users.

Crypto & Web3Fintech

NNNick Neuman(Founder & CEO)in

Co-investorsCHChampion Hill VenturesF-F-Prime CapitalFAFabric VenturesFUFulgur VenturesSTSTILLMARKTITioga Capital Partners+4 more

Coala Pay simplifies cross-border money transfers for humanitarian aid organizations, delivering more local currency than traditional banking rates.

Crypto & Web3FintechImpact & Social GoodSaaS

Co-investorsCVCV VCLALattice CapitalREReflexive CapitalCOCommerce VenturesFAFactor Capital

Cyclops is a unified crypto and stablecoin platform built specifically for payments companies, combining licensing, custody, compliance, and 24/7 settlement into a single integration.

Crypto & Web3FintechSaaS

AWAlex Wilson(Founder)in

Co-investorsF-F-Prime CapitalNANava VenturesCICircle & Co.COCoinbase Ventures

Cyclops Medtech develops a portfolio of vestibular diagnostic and therapy products—including videonystagmography (VNG/VOG), video head impulse testing (vHIT), dynamic visual acuity, stabilometry platforms, VR-based vestibular rehabilitation, and a smart balance board—to diagnose and treat dizziness and balance disorders.

Digital HealthHealthtechMedical Devices

Co-investorsCACapria VenturesCICircle & Co.COCoinbase VenturesNANava Ventures

Provides crypto solutions for institutions.

Christopher King(Founder)in

Co-investorsHAHack VCBRBrewer Lane VenturesFRFranklin Templeton

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-investorsBRBrewer Lane VenturesF-F-Prime CapitalAVAvon VenturesFLFlyover CapitalFRFranklin TempletonGEGemini Frontier Fund+2 more

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

Palmer Luckey(Founder)

Co-investorsANAntiARArctic DigitalBABalerion Space VenturesINIneffable VenturesLALakeside CapitalLULux Capital+12 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

BGBernardo Garcia(Founder)in

Co-investorsCOContour Venture PartnersDODorm RoomHTHTwentyMOMONASHEESQEQED InvestorsSWSwitch 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

CLChris Lehman(Founder)inGFGrant Fishman(Founder)in

Co-investorsBABantam GroupCOCoinbase VenturesLALaunchpad 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

SASam Abbassi(CEO)inCWCory Wilbur(CTO and Head of Product)in

Co-investorsF-F-Prime CapitalFUFulgur VenturesSTSTILLMARKAVAvon VenturesTETen31

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

CMConnor McKenzie(Founder)in

Co-investorsNXNxGenPRPragma VenturesREReciprocal VenturesBRBrevan Howard DigitalFIFinTech Collective

Manetu provides access control and policy enforcement for data, APIs, and AI systems in real time.

AI & Machine LearningCybersecurityData & InfrastructureEnterprise SoftwareRidgewood, US

DHDavid Harris(Executive Officer, Director)inMoiz Kohari(Executive Officer, Director)Gregory Haskins(Executive Officer)Richard Hurwitz(Executive Officer)Anand Babu Periasamy(Director)inKurt Dalton(Director)

Meow is a financial technology company offering business banking, corporate cards, global payments, invoicing, and crypto services, including a Commercial Paper Account for earning yield on idle cash.

AI & Machine LearningEnterprise SoftwareFintech

BABrandon Arvanaghi(Founder)inBryce Crawford(Cofounder)

Co-investorsACAcequia Capital (AceCap)ACAcrew CapitalACAcrylicCOCoinbase VenturesEAEarl Grey CapitalFOFounders Fund+15 more

Mint Songs was a music NFT marketplace for artists, acquired by Napster in February 2023 after winding down operations.

Co-investorsAAAAF Management Ltd.COCoinbase VenturesEAEast West Ventures EWVFRFreestyle Capital

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

MMMatt Marcus(Co-Founder & CEO)inDDDimitri Dadiomov(Cofounder & CEO)inSASam Aarons(Co-Founder & CTO)in

Co-investorsARArchetypeARArtisanal VenturesCLCleo CapitalMIMischiefNENewView CapitalQUQuiet Capital+7 more

Mountain Protocol offers a regulated, enterprise-grade stablecoin product designed to pass the "risk free rate" to stablecoin holders, acting as a bridge between crypto and traditional finance markets.

Crypto & Web3Fintech

Co-investorsCOCoinbase VenturesDEDepartment of XYZMUMulticoin CapitalVEVenture Dept.BABankless Ventures

Nirvana Labs provides bare-metal cloud compute instances across three families optimized for different workloads, with pricing up to 37% lower than AWS equivalents.

AI & Machine LearningCloud ComputingData & InfrastructureDeep TechDeveloper ToolsEnterprise Software

Co-investorsCRCrucible CapitalHAHash3 CapitalLALattice CapitalRARaptor GroupVAVarys CapitalJUJump Crypto+1 more

Notabene provides compliance and regulatory technology for crypto businesses and financial institutions, helping them meet regulatory requirements like the FATF Crypto Travel Rule through real-time screening, sanctions checks, and wallet identification.

Crypto & Web3CybersecurityEnterprise SoftwareFintechNew York City, US

PBPelle Braendgaard(CEO/ Co-Founder)inAJAndres Junge(Founder)inALAnia Lipinska(Founder)inANAlice Nawfal(Founder)in

BoardMatthew Walsh(Director)PJPeter Johnson(Director)in

Co-investorsDIDigital Currency GroupF-F-Prime CapitalPAParaFi CapitalSISignature VenturesWIWintermuteY Y Combinator+10 more

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

Co-investorsCOCoinbase VenturesFIFin CapitalLALattice CapitalQUQuantonationVAVariant FundBABalaji Srinivasan+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-investorsFUFuture Perfect VenturesHAHash3 CapitalANAntlerCOCoinbase VenturesFOForce Ventures

W. Aaron Daniel(Founder)inDave Schwab(Founder)in

Co-investorsDRDraper AssociatesDRDraper Dragon

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)Christian Larsen(Executive Officer, Director, Promoter)DSDavid Schwartz(Director)inBradley Garlinghouse(Executive Officer)

BoardYoung Guo(Director)Doug Chertok(Director)

Co-investors50500 GlobalABAbstract VenturesAUAurum Venture PartnersAVAvant Global LLCCACamp One VenturesCOCore Venture Capital+19 more

SatLayer is a Bitcoin restaking protocol that lets holders deposit Bitcoin or liquid staking tokens into vaults to earn rewards and provide shared security for Bitcoin Validated Services (BVSs).

Crypto & Web3Data & InfrastructureFintech

LXLuke Xie(Founder)in

Co-investorsBLBloccelerate VCHAHack VCASAsymmetricMIMirana VenturesOKOKX Ventures

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

AHAdam Healy(Founder)inAEAdam Everspaugh(Founder)in

Co-investorsA1A100X VenturesMEMetalayerSCSCB 10XNONotation CapitalSESemantic Ventures

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

Crypto & Web3Data & InfrastructureFintechSaaS

AKAnton Katz(Founder & CEO)in

Co-investors1010SQ Capital (TenSquared)A1a16z cryptoANAndreessen HorowitzCOCoinbase VenturesELElefundFIFin 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

GPGeetha Panchapakesan(Founder)in

Co-investorsDIDigital Currency GroupSTStrobe 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

ECEsteban Castaño(Founder)inRRRahul Raina(Founder)inSRSujit Raman(Chief Legal Officer)inARAri Redbord(Global Head of Policy)inTATom Armstrong(Head of Compliance Advisory)

Co-investorsALAlumni VenturesB B Capital GroupB4B4 CapitalBABasecamp FundBEBessemer Venture PartnersGEGeodesic 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-investorsCACampus Founders FundHAHarpoon VenturesMYMythos Ventures Management, LlcMAMaven 11

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

Crypto & Web3FintechNew York, US

LYLily Yarborough(Co-Founder and CBO)inCDConnor Dougherty(Co-Founder and CEO)in

BoardSJSean Judge(Director)inNazar Khan(Director)

Co-investorsDEDepartment of XYZMAMaven 11VEVenture Dept.

Yellow.ai is an agentic AI platform for customer service automation that uses multi-LLM architecture and conversational data to help enterprises reduce operational costs and improve customer interactions.

AI & Machine LearningEnterprise SoftwareSaaSBangalore, IN

RKRashid Khan(Founder)inJKJaya Kishore Reddy Gollareddy(Founder)inRRRaghu Ravinutala(Founder)in

Co-investorsSASapphire VenturesBLBlockchain.com VenturesCOCoinbase VenturesFAFabric VenturesMOMoonPayPOPolychain Capital+2 more

YellowSculpt provides AI-powered 3D character generation software that converts text prompts into fully rigged, animation-ready models for studios and game makers.

AI & Machine LearningGamingPalo Alto, US

MWMandeep Waraich(Founder and CEO)inVSVincent Sitzmann, PhD(Co-founder and Chief Scientist)

Co-investorsANAndreessen HorowitzBLBlockchain.com VenturesCOCoinbase VenturesFAFabric VenturesMOMoonPayPOPolychain Capital+2 more

Yellow Card is a licensed stablecoin infrastructure provider operating across Africa, offering cryptocurrency and payment services aimed at solving financial, regulatory, and logistical problems in emerging markets.

Crypto & Web3Fintech

CMChris Maurice(Co-founder & CEO)inJustin Poiroux(Co-founder & CTO)in

Co-investorsATAtlanta Technology AngelsDGDG Daiwa VenturesFAFabric VenturesFEFenbushi CapitalPHPharsalus CapitalSOSony Ventures Corporation+3 more

ZenLedger provides tax and accounting software that automates cryptocurrency tax calculations for crypto traders, investors, and tax professionals.

Crypto & Web3FintechSaaSSeattle, US

PLPatrick Larsen(Founder & CEO)inDEDaniel Escobar(Chief Technology Officer)in

BoardMCMark Casady(Director)in

Co-investorsBLBloccelerate VCBOBorderless VentureCOConvergeKIKing River CapitalOSOssian CapitalPAParaFi Capital+9 more