Fundraising Fox
Castle Island Ventures
Venture capitalActively deployingBoston · Pre-Seed–Series A · 14 people tracked
Also known as Castle Island · CASTLE ISLAND MANAGEMENT, LLC
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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 Sep 29, 2026.
Team · 14 people
from the firm's website & curated & public directories
What they invest in
from 56 of 74 portfolio companiesCrypto & Web3 ×40Fintech ×37Enterprise Software ×14AI & Machine Learning ×13Data & Infrastructure ×13SaaS ×10Cybersecurity ×9Cloud Computing ×4
HQs:United States×32Colombia×1United Kingdom×1India×1
Who they back
founder profiles across 17 portfolio companiesFounding team size:solo founder×32 founders×93 founders×24+ founders×3
Where their founders studiedfrom 26 founders with education data
Massachusetts Institute of Technology ×5Dartmouth College ×2Harvard Business School ×2Princeton University ×2The Wharton School ×2University of Michigan ×2
What their founders studiedfrom 25 founders with field-of-study data
Computer Science ×11Engineering ×6Business & Management ×3Economics ×3Finance & Accounting ×2
Where their founders worked beforefrom 29 founders with career history
Microsoft ×6McKinsey & Company ×3MIT Media Lab ×3Revolut ×3Bitwise Asset Management ×2BlockFi ×2
Accelerator rootsportfolio companies that came through a program
2 founders hold a PhD · 3 hold an MBA (of 28 with degree data)
Investments · 74 tracked
founders shown can be your intro pathBy year:2026 · 92025 · 102024 · 92023 · 52022 · 82021 · 52020 · 12019 · 12018 · 149 dated
Moonwalk is a fitness accountability app built on the Solana blockchain where users pool crypto with friends, set step-based goals tracked via fitness apps, and redistribute deposits between participants based on who meets the goals.
Crypto & Web3Sports TechWellness & Fitness
Nom(Co-Founder)kw(Co-Founder)Swol Sol(Co-Founder)
Co-investorsFramework VenturesMonadMulticoin CapitalSolana FoundationSolana LabsFlowdesk+1 more
Phylax builds the Credible Layer, a policy engine that lets on-chain protocols declare states they must never reach and enforces circuit breakers that reject transactions crossing those limits.
Crypto & Web3CybersecurityEnterprise SoftwareNew York, US
Odyssefs Lamtzidis(Executive Officer, Director)Evangelos Ntomprozis(Executive Officer)
Co-investorsBankless VenturesBreedFigmentHash3 CapitalBreed VCFigment Capital+2 more
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)inMatthew Green(Co-founder)inEran Tromer(Co-founder)in
Co-investorsFireblocksRibbit CapitalCoinbase VenturesDigital Currency GroupGalaxy VenturesGemini Frontier Fund+1 more
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)in
Co-investorsHaun VenturesOak HC/FTCoinbase VenturesMAYA CapitalMAYA Capital VenturesPaxos
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
Tim Rice(Founder)inAleksei Nokhrin(Founder)Alexander Bich(Founder)Jacob Franek(Founder)
BoardMathew S. McDermott(Director)Sean Judge(Director)in
Board seatNic Carter· per SEC Form D · $6.7M raise · filed Oct 2023
Co-investorsAcrew CapitalBlockchain CoinvestorsCoinbase VenturesCollab+CurrencyCommunitas Capital PartnersDigital Currency Group+10 more
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 & Web3FintechSaaSMiami, US
Alex Wilson(Founder)in
Board seatSean Judge· per SEC Form D
Co-investorsF-Prime CapitalNava VenturesCircle & Co.Coinbase Ventures
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
Jon Pilon(Executive Officer)inAydin Mohtashamian(Executive Officer)inJohn D Parkes(Executive Officer, Director)in
BoardRobert Miller(Director)David Gross(Director)
Board seatGus Coldebella· per SEC Form D · $90.7M raise · filed Nov 2024
Co-investorsTeamworthy VenturesTrue 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(Founder & CEO)in
Board seatNic Carter· per SEC Form D · $10.6M raise · filed Mar 2025
Co-investorsFinancial Venture StudioProtagonistRestive Ventures
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A DeFi protocol creating a marketplace for blockspace.
Co-investorsBODLCircle VenturesCoinbase Ventures1kxDragonflyRobot Ventures+1 more
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(Chief Operating Officer)inPramod Kandel(Chief Technology Officer)inSimanta Gautam(Chief Executive Officer)inChandan Sharma Subedi(Co-Founder)inJohn LightinTrey Del Bonis
Co-investorsAccelmed PartnersAsymmetricHivemind Ventures, LlcLaunchpad CapitalMirana VenturesResolute Ventures+8 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)inJames Smits(Founder)inNick De Veaux(Founder)
Co-investors645 VenturesAfore CapitalBollinger Investment GroupCalm VenturesChaos VenturesChapter One+10 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-investorsArca FundsArchetypeSoma CapitalBlocktower CapitalEniac Ventures
Arch provides AI-powered software for home services contractors in HVAC, plumbing, and electrical to identify sales prospects, detect at-risk customers for retention, and uncover upsell opportunities.
AI & Machine LearningMarketing TechSaaSSan Francisco, US
Phil K.(Founder)inJason Meltzer(Founder)Jason Trigg(Founder)Joel Stein(Founder)Phil Krinner(Founder)Philipp Krinner(Founder)
Co-investorsCoatue ManagementFloodgateGigascale CapitalOak HC/FTAsymmetricCiti Ventures+8 more
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
Dhruv Patel(CEO & Co-founder)inHimanshu Sahay(CTO & Co-founder)in
Co-investorsAlumni VenturesBBQ CapitalFormus CapitalFour Acres CapitalPICUS CAPITALRaido Venture 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(Founder)inZach Garman(Founder)inAlvaro Correa(Founder)inÁlvaro Correa Gallardo(Founder)inÁlvaro Correa(Founder)in
Co-investorsCircle VenturesFounders FundKaszek VenturesSequoia CapitalY Combinator11 11 DG Partners+9 more
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 VC1kxSeed 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-investors5Lion Ventures1kxPlaceholder VCSeed 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
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 Vekiarides(Executive Officer, Director)inJohn Bates(Executive Officer, Director)inThomas Mark Morley(Executive Officer)Emmanuel Parasirakis(Executive Officer)in
BoardMatthew Walsh(Director)inJason Weiss(Director)in
Co-investorsBlockchain CoinvestorsBorderless 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 & Web3Fintech
Fisher Yu(Founder)inDavid Tse(Founder)
Co-investorsa16z cryptoAlumni VenturesAndreessen HorowitzBasecamp FundBloccelerate VCBreyer Capital+13 more
Birch Hill provides infrastructure and risk management tools for institutional investors to allocate capital and trade assets on blockchain networks.
Crypto & Web3Data & InfrastructureFintechOld Westbury, US
Raizada Bhavin Vaid(Executive Officer, Director, Promoter)Jack Forlinesin
BoardConnor Flanagan(Director)Shayon Sengupta(Director)
Co-investorsParaFi CapitalParafi General FundFalconX VenturesFlowdesk
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
Kevin FarrellyinGreg ScanloninJames McClain
Co-investorsDepartment of XYZMetalayerVenture Dept.
Bitwise offers professionally managed crypto investment funds and products, including ETFs, separately managed accounts, private funds, and staking.
Crypto & Web3FintechSan Francisco, US
Hong Kim(Founder)inHunter Horsley(Founder)inKatherine Dowling(Executive Officer)inMatt Hougan(Executive Officer)inTeddy Fusaro(Executive Officer)in
BoardCorey Mulloy(Director)
Co-investorsBlockchain CapitalBlockchain CoinvestorsChorus OneCoinbase VenturesCollaborative FundCraft Ventures+13 more
Casa provides self-custody solutions for bitcoin and stablecoins, offering multi-signature security infrastructure for both individual and institutional users.
Crypto & Web3Fintech
Nick Neuman(Founder & CEO)in
Co-investors515 VenturesAcrew CapitalBlockchain CoinvestorsChampion Hill VenturesCoinbase VenturesF-Prime Capital+11 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-investorsCV VCFactor CapitalLattice CapitalReflexive CapitalCommerce 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-investorsCapria VenturesCircle & Co.Coinbase VenturesF-Prime CapitalNava Ventures
Dust Identity develops physical identity solutions using diamond-based technology to authenticate and trace high-value products and components across supply chains.
Circular EconomyDeep TechDefense TechEnterprise SoftwareHardwareIoTNew MaterialsRetail TechNeedham, US
Ophir Gaathon(Founder)inDirk Englund(Founder)
BoardIlya Fushman(Director)in
Co-investorsAlumni VenturesAngular VenturesBlockchain CoinvestorsF-Prime CapitalGrit VenturesMotier Ventures+7 more
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 CapitalHack VCAvon VenturesFlyover CapitalFranklin Templeton+3 more
Erebor is a US national bank in Columbus, Ohio serving AI, crypto, defense and advanced manufacturing companies.
Palmer Luckey(Founder)
Co-investorsAntiArctic DigitalBalerion Space VenturesChapter OneIneffable VenturesInnova Capital Partners, LLC+20 more
Jacob Hirshman(Founder)Joe Lonsdale(Founder)Owen Rapaport(Founder)Palmer Luckey(Founder)
Co-investorsHaun VenturesHuman CapitalHypersphere VenturesLux CapitalSeven Seven Six
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)inJuan Llanos(Executive Officer)in
BoardManuel Godoy(Founder)inSean Judge(Director)inPaul Arnold(Director)inAna Cristina Gadala-Maria(Director)in
Co-investorsContour Venture PartnersDorm RoomGeneral CatalystHTwentyMONASHEESQED Investors+9 more
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Fordefi provides an MPC (multi-party computation) wallet with DeFi-specific features for institutional users such as blockchain investment funds, supporting multi-chain token strategies.
Crypto & Web3CybersecurityFintech
Josh Schwartz(Founder)inJosh shwartz(Founder)inDima Kogan(Founder)Michael Volfman(Founder)
Co-investorsDelta BlockchainDigital Currency GroupElectric CapitalLemniscapLightspeed Venture PartnersM12 (Microsoft's Venture Fund)+9 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 & Web3FintechPropTechBoston, US
Chris Lehman(Founder)inGrant Fishman(Founder)in
Co-investorsBantam GroupCoinbase VenturesLaunchpad Venture Group
Halborn is a blockchain security firm that provides smart contract auditing, penetration testing, red team simulations, and advisory services for enterprises, financial institutions, and blockchain ecosystem leaders.
Crypto & Web3CybersecurityEnterprise Software
Co-investorsDigital Currency GroupThird PrimeSummit Partners
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)inCory Wilbur(CTO and Head of Product)in
Co-investorsF-Prime CapitalFulgur VenturesSTILLMARKTen31Valor Equity PartnersAvon Ventures
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 VenturesPurechain CapitalReciprocal VenturesBrevan Howard DigitalFinTech Collective
Manetu provides access control and policy enforcement for data, APIs, and AI systems in real time.
AI & Machine LearningCybersecurityData & InfrastructureEnterprise SoftwareRidgewood, US
David Harris(Executive Officer, Director)inMoiz Kohari(Executive Officer, Director)Gregory Haskins(Executive Officer)Richard Hurwitz(Executive Officer)Anand Babu Periasamy(Director)inKurt Dalton(Director)
Co-investorsBlockchain Coinvestors
Meow is a financial technology company offering a business banking platform for companies and AI agents, combining checking accounts, corporate cards, global payments, invoicing, financing, and crypto.
AI & Machine LearningEnterprise SoftwareFintechMiami Beach, US
Brandon Arvanaghi(Founder)inBryce Crawford(Founder)
Co-investorsAcequia Capital (AceCap)Acrew CapitalArchetypeCoinbase VenturesEarl Grey CapitalKairos Angels+16 more
Mint Songs was a music NFT marketplace for artists, acquired by Napster in February 2023 after winding down operations.
Co-investorsAAF Management Ltd.Coinbase VenturesEast West Ventures EWVFreestyle 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
Matt Marcus(Founder)inDimitri Dadiomov(Founder)inSam Aarons(Founder)in
Co-investorsArchetypeArtisanal VenturesCervinCleo CapitalFour CitiesMischief+16 more
Monad is a high-performance EVM-compatible blockchain designed for fast, low-cost transactions.
Cloud ComputingCrypto & Web3Data & InfrastructureCalifon, US
Eunice Giarta Hon(Executive Officer)James Hunsaker(Founder)Keone Hon(Founder)inEunice Giarta(Founder)
Co-investorsAlphaLab CapitalAmbush CapitalArchetypeBankless VenturesBig Brain HoldingsBloccelerate VC+33 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
Martin Carrica(Founder)Matias Caricato(Founder)
Co-investorsCoinbase VenturesDepartment of XYZMulticoin CapitalVenture Dept.Bankless VenturesWormhole Capital
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-investorsCrucible CapitalHash3 CapitalLattice CapitalRaptor GroupVarys CapitalJump 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
Pelle Braendgaard(Founder)inAndres Junge(Founder)inAnia Lipinska(Founder)inAlice Nawfal(Founder)in
BoardMatthew Walsh(Director)Peter Johnson(Director)in
Co-investorsBlockchain CoinvestorsDigital Currency GroupF-Prime CapitalNextBlockParaFi CapitalParafi General Fund+16 more
Project Eleven builds post-quantum cryptography and migration tooling for Bitcoin, Ethereum and other digital asset networks.
Co-investorsCoinbase VenturesFin CapitalLattice CapitalQuantonationVariant FundBalaji 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-investorsAntlerBharat Founder's FundFuture Perfect VenturesHash3 CapitalBalaji SrinivasanCoinbase Ventures+1 more
Rally is an investment platform that lets people buy and sell equity shares in collectible assets, which are securitized into individual companies and offered as shares through registered broker dealers.
FintechMarketplacesNew York City, US
Maximilian Niederste-Ostholt(Founder)Rob Petrozzo(Founder)in
Co-investorsAccelAnthemis VentureGlobal BrainKDDI Open Innovation FundRaptor GroupRed Beard Ventures+11 more
W. Aaron Daniel(Founder)inDave Schwab(Founder)in
Co-investorsDraper AssociatesDraper 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)David Schwartz(Founder)inBradley Garlinghouse(Executive Officer)Arthur Britto(Founder)Brad Garlinghous(Founder)
Co-investors500 GlobalAbstract VenturesAurum Venture PartnersAvant Global LLCCamp One VenturesCore Venture Capital+22 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
Co-investorsAsymmetricBloccelerate VCHack VCBing VenturesMirana VenturesOKX Ventures
Allentown, US
Jared Isaacman(Executive Officer, Director)Bradley Herring(Chief Financial Officer)Jordan Frankel(General Counsel and Secretary)inTaylor Lauber(President and Chief Strategy Officer)inDonald Isaacman(Director)Nancy Disman(Director)
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)in
Co-investorsA100X VenturesMetalayerSCB 10XCyberstartsNotation 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)inEthan Feldman(Founder)
Co-investors10SQ Capital (TenSquared)a16z cryptoAndreessen HorowitzBlockchain CoinvestorsCoinbase VenturesElefund+17 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)inAri Redbord(Global Head of Policy)inTom Armstrong(Head of Compliance Advisory)
Co-investors10T FundAlumni VenturesB Capital GroupB4 CapitalBasecamp FundBessemer Venture Partners+35 more
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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 FundHarpoon VenturesMythos 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(Co-Founder and CBO)inConnor Dougherty(Co-Founder and CEO)in
BoardSean Judge(Director)inNazar Khan(Director)
Co-investorsDepartment of XYZMaven 11Venture Dept.
Valiu provides mobile banking services that give individuals and businesses in Latin America access to U.S. dollars and other stable currencies in markets where local money loses value or experiences high inflation.
Crypto & Web3FintechBogotá, CO
David Barinas(Founder)inSimon Chamorro(Founder)in
Co-investorsBlockchain CoinvestorsITERATIVEY Combinator10X CapitalAHP InvestmentsAusum Ventures+10 more
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
Rashid Khan(Founder)inJaya Kishore Reddy Gollareddy(Founder)inRaghu Ravinutala(Founder)inJaya Kishore Gollareddy(Founder)Jaya Kishore Reddy(Founder)
Co-investorsLightspeed India PartnersLightspeed Venture PartnersSapphire VenturesTitan CapitalBlockchain.com VenturesBlume Ventures+6 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
Mandeep Waraich(Founder)inVincent Sitzmann, PhD(Co-founder and Chief Scientist)
Co-investorsAndreessen HorowitzBlockchain.com VenturesCoinbase VenturesFabric VenturesMONASHEESMoonPay+3 more
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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 & Web3FintechBirmingham, US
Chris Maurice(Founder)inJustin Poiroux(Founder)inKeith Hamlin(Director)Jason Marshall(Executive Officer)Joshua Rosenthal(Director)
BoardAleks Larsen(Director)in
Co-investorsAtlanta Technology AngelsBlockchain CapitalDG Daiwa VenturesFabric VenturesFenbushi CapitalPharsalus Capital+7 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)inDaniel Escobar(Chief Technology Officer)in
BoardMark Casady(Director)in
Co-investorsBloccelerate VCBlockchain CoinvestorsBorderless VentureConvergeFJ LabsG1 Ventures+16 more
Other
Tracked investments with no reachable website or further public details — typically companies that wound down, renamed, or were absorbed.
ArcadeArnac Software Ltd.AtriumBeamBuild on BitcoinL2Pear ProtocolRockSolid NetworkSendblocksTry Your Best
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.
Portfolio news
latest coverage across their companies
Erebor · pymnts.com · Aug 10, 2026
Birdai · fintech.global · Jul 29, 2026
Notabene · fintech.global · Jul 28, 2026
Cyclops · fintech.global · Jul 17, 2026
Ripple Labs · finance.yahoo.com · Jul 14, 2026
Valinor Digital · finsmes.com · Mar 31, 2026
TRM Labs · finsmes.com · Feb 4, 2026
Project Eleven · securityweek.com · Jan 16, 2026
Frequently asked questions
- How many investments has Castle Island Ventures made?
- Castle Island Ventures has 74 tracked investments, 3 of which have exited, including 21 dated in the last 24 months.
- 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.
- Who does Castle Island Ventures co-invest with?
- Castle Island Ventures most often shares deals with Coinbase Ventures, Blockchain Coinvestors, Alumni Ventures, among 167 tracked co-investors.
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 teamCan Bitcoin Survive AI & Quantum? with Nic Carter | Galaxy Brains
Galaxy · Nic Carter
The Politics of Post-Quantum Bitcoin | NIC CARTER
Isabel Foxen Duke · Nic Carter
Bitcoin Has 3 Years to Survive the Quantum Threat | Nic Carter
Bankless · Nic Carter
Nic Carter: Quantum Threatens $600B of Bitcoin
Delphi Digital · Nic Carter
Nic Carter - Cryptodollarization: The Emerging Markets Story - TOKEN2049 Singapore 2024
TOKEN2049 · Nic Carter
Will Stablecoins Serve or Subvert US Interests
Messari · Nic Carter
Images
Co-investors · 20
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.
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.
Hack VC is a venture capital firm investing in early-stage crypto, blockchain infrastructure, decentralized finance, and AI companies.
Initialized Capital is a seed-stage venture firm that partners with founders very early — often before product-market fit — providing hands-on support across product, recruiting, go-to-market, PR, and Series A fundraising.
Stillmark is a venture capital firm that invests in companies building products and infrastructure for a bitcoin-powered future.
Robot Ventures is a $75M early-stage crypto fund founded and led by Robert Leshner (Compound) and Tarun Chitra (Gauntlet), who actively run major DeFi companies while managing the fund, giving founders direct access to operators at the center of on-chain markets. The fund specializes in backing highly technical crypto primitives at the pre-seed stage before they become marquee names, leveraging deep quant research expertise to evaluate complex DeFi mechanisms that many generalist VCs struggle to understand.
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.
Cyberstarts is a venture capital firm that partners with cybersecurity founders from day one, using a systematic process and an extensive CISO network to help build industry-defining cybersecurity companies.
Shima Capital is a $200M web3 seed fund led by Forbes 30 Under 30 investor and MIT instructor Yida Gao, who combines traditional finance, venture capital, and academic credentials rare among dedicated crypto funds. The firm maintains one of the highest early-stage deployment paces in crypto with over 100 investments in two years, using more than half its team for hands-on operational support through a proprietary platform that helps portfolio companies with talent, tokenomics, and specialized expertise like gaming.
AirTree Ventures runs Pathfinders, a free four-week in-person program in Sydney for young builders (high-school graduates up to age 23) to work on a real product, access the AirTree team and founders, and build a peer network.
Champion Hill Ventures is an early-stage venture firm, founded in 2014, that backs founders tackling large, overlooked problems through non-consensus and structurally underserved ideas.
▶8 more co-investors
CadenzaRed Swan VenturesM13PolygonThe Venture CollectiveSolana VenturesBlockchain Founders FundLakehouse 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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