About Castle Island Ventures
Castle Island Ventures is a venture capital firm founded in 2018. It is primarily based out of Cambridge, United States. As of Sep 2026, Castle Island Ventures is an active investor, having invested in 81 companies, with 8 new investments in the last 12 months. It primarily invests in Seed round in United States based startups. Its investments are spread across a wide range of sectors from Blockchain Technology to High Tech and Enterprise Applications. Most recently it participated in the $***** Series B round of Felix Overall, Castle Island Ventures portfolio has seen 4 unicorns, 1 IPO and 11 acquisitions including key companies like MoonPay, BlockFi and Bitwise. A lot of funds co-invest with Castle Island Ventures, with names like Coinbase sharing a substantial percentage of its portfolio. Castle Island Ventures has team of 4 people including 4 partners.Key Metrics
Team Members
Portfolio Count
Portfolio Sectors
Portfolio Locations
Rounds of Entry
Seed, Series A & 2 more
Portfolio IPOs
Portfolio Soonicorns
Deals in last 12 months
Castle Island Ventures' List of Top Investments
Castle Island Ventures has a portfolio of 81 companies, including 4 unicorns. Their most notable investments are in hoseki and Coin Metrics.Their portfolio spans across United States, United Kingdom, Canada and 12 more locations. They have invested in Blockchain Technology, High Tech, Enterprise Applications and 11 other sectors, across stages such as Seed, Series A and 2 more. Here is the list of top investments by Castle Island Ventures:1. MoonPay
Provider of platform for buying, selling, and swapping various cryptocurrencies. The platform facilitates the instant purchase of cryptocurrencies using various payment methods. It also enables users to sell cryptocurrencies directly to their bank accounts or cards. Additionally, the platform offers the ability to send and receive cryptocurrencies.
Key facts about MoonPay
- Founded Year: 2018
- Location: Dover (United States)
- Valuation: $*****
- Stage: Series A
- Total Funding till date: $645M
- Employee Count: 467 as on Jul 31, 2026
- Investors: K2 Global, ARTFO Holdings and 81 Others
- Latest Funding Round: Conventional Debt, Mar 21, 2025, $*****
- Highlight: Editors' Pick
Key facts about River Financial
- Founded Year: 2019
- Location: San Francisco (United States)
- Stage: Series B
- Total Funding till date: $70M
- Employee Count: 143 as on Jul 31, 2026
- Investors: Creative Capital, The Kraft Group and 20 Others
- Latest Funding Round: Series B, May 16, 2023, $*****
- Highlight: Editors' Pick
3. BlockFi
Online platform for trading, crypto-backed loans, interest accounts, and wallets. The platform tracks all the historical transaction details and assists in tax reporting. It also offers solutions for miners, exchanges, and Crypto ATMs. Its app is available for Android and iOS users.
Key facts about BlockFi
- Founded Year: 2017
- Location: Jersey City (United States)
- Last Known Valuation: $*****
- Stage: Acquired
- Total Funding till date: $466M
- Employee Count: 178 as on Jul 31, 2026
- Investors: Fidelity Investments, Bracket Capital and 63 Others
- Latest Funding Round: Conventional Debt, Jun 22, 2022, $*****
- Highlight: Acquired
4. Pintu
App-based platform for storing, buying, and selling digital assets and cryptocurrencies. It offers a deposit account, exchange platform, digital wallet for storing and receiving digital assets, and more. The application is available on iOS and Android devices.
Key facts about Pintu
- Founded Year: 2016
- Location: Jakarta (Indonesia)
- Valuation: $*****
- Stage: Series B
- Total Funding till date: $154M
- Employee Count: 960 as on Jul 31, 2026
- Investors: Lightspeed Venture Partners, Castle Island Ventures and 8 Others
- Latest Funding Round: Series B, Jun 06, 2022, $*****
- Highlight: Editors' Pick
5. Bitwise
Provider of crypto index funds, ETFs, and managed accounts. It offers professionally managed funds focused on the crypto asset class. The firm provides various investment products, including ETFs, publicly traded trusts, SMAs, and private funds, offering exposure to multiple crypto assets, equities, hedge funds, and NFT collections. The company focuses on providing investors access to the crypto space through its investment solutions.
Key facts about Bitwise
- Founded Year: 2017
- Location: San Francisco (United States)
- Stage: Public
- Total Funding till date: $91.2M
- Employee Count: 152 as on Jul 31, 2026
- Investors: Inflection Ventures, Collab Fund and 41 Others
- Latest Funding Round: Post IPO, Feb 25, 2025, $*****
- Highlight: Public
Castle Island Ventures' Year-on-Year Investment Trends
Castle Island Ventures has invested in 81 companies over the last 8 years, with an average of 11 new investments annually in the last 5 years. In 2025, it made 16 investments, while as of Sep 2026, it has made 7 investments in this year. Its most recent first time investment was in Birdai Labs and most recent follow-on round was in Felix.Year | No. of Investments | ||
|---|---|---|---|
1st Round | Follow-on | Total | |
2026 (YTD) | 4 | 3 | 7 |
2025 | 10 | 6 | 16 |
2024 | 12 | 4 | 16 |
2023 | 6 | 2 | 8 |
2022 | 19 | 3 | 22 |
2021 | 11 | 6 | 17 |
2020 | 8 | 1 | 9 |
2019 | 2 | 3 | 5 |
2018 | 2 | 0 | 2 |
Castle Island Ventures' Investments by Stage
Castle Island Ventures has made 48 investments in Seed stage with an average round size of $6.55M, 20 investments in Series A stage with an average round size of $17.4M, 5 investments in Series B stage with an average round size of $39.6M and 1 investment in Series C stage with an average round size of $350M.Stage of entry | No. of Investments |
|---|---|
Seed | 48 |
Series A | 20 |
Series B | 5 |
Series C | 1 |
Note: We have considered here, only first round of investments
Castle Island Ventures' Investments by Sector
Castle Island Ventures has a diverse portfolio, with companies operating in the FinTech, Blockchain Technology, Blockchain - Industry Applications, High Tech and Enterprise Applications. Notably, it has invested in 76 Tech companies, 56 Blockchain companies, 47 Enterprise (B2B) companies and at least 45 companies focusing on Consumer (B2C).Sector | No. of Investments |
|---|---|
FinTech | 53 |
Blockchain Technology | 52 |
Blockchain - Industry Applications | 43 |
High Tech | 34 |
Enterprise Applications | 23 |
Others | 35 |
Note: We have considered here, only first round of investments
Castle Island Ventures' Investments by Geography
Castle Island Ventures has made most investments in United States (54), followed by United Kingdom where it has made 5 investments.Country | No. of Investments |
|---|---|
United States | 54 |
United Kingdom | 5 |
Canada | 1 |
Colombia | 1 |
France | 1 |
Others | 9 |
Note: We have considered here, only first round of investments
Castle Island Ventures' recent investments
Castle Island Ventures has made 7 investments in 2026 so far. Felix and Birdai Labs are the latest among them.Here are the most recent investments by Castle Island Ventures:
Filter this listDate | Company | Location | Round Details | Round Amount | Co-Investors |
|---|---|---|---|---|---|
Sep 01, 2026 | United States | Series B | 1428 | [+4] | |
Jul 28, 2026 | United States | Seed | 6220 | [+1] | |
Jul 02, 2026 | United States | Series A | 1355 | [+4] | |
Mar 26, 2026 | United States | Series A | 4195 | [+1] | |
Mar 04, 2026 | United States | Seed | 5813 | [+1] |
Unicorns in Castle Island Ventures' Portfolio
Castle Island Ventures has 4 unicorns in its portfolio - TRM Labs, Talos, Crusoe and others. The most recent unicorn in their portfolio is TRM Labs. It became a unicorn in 2026, 4 years after Castle Island Ventures first invested in it.Here is a list of unicorns in Castle Island Ventures' portfolio:
Tracxn Score | Company | Short Description | Founded year | Sector | Location | Company Stage | First Investment/ Acquisition Details |
|---|---|---|---|---|---|---|---|
66 | Provider of blockchain intelligence for detecting crypto-facilitated crime and compliance | 2018 | San Francisco | Series C | tilehnf | ||
69 | Provider of an institutional digital assets platform for trading, managing, and accessing crypto markets | 2018 | New York City | Series B | ehkmugv | ||
66 | Operator of cloud platform providing infrastructure for artificial intelligence workloads | 2018 | Denver | Series F | fbnjixv | ||
81 | Provider of platform for buying, selling, and swapping various cryptocurrencies | 2018 | Dover | Series A | afmeomi |
IPOs and Publicly Listed companies in Castle Island Ventures' Portfolio
1 of Castle Island Ventures' portfolio company became public - Bitwise. It got listed on the American Stock Exchange (NYSEAMERICAN), in Jan 2024.Here are Castle Island Ventures' portfolio companies that went public:
Company | IPO Date | First Invested on | First Round of Investment | Round Size |
|---|---|---|---|---|
Jan 11, 2024 | Jun 15, 2021 | Series B | 2146 |
Acquired companies in Castle Island Ventures' Portfolio
11 companies from Castle Island Ventures' portfolio have been acquired. The most recent acquisition was Fordefi in Nov 2025 by Paxos for $*****.Here are Castle Island Ventures' portfolio companies that got acquired most recently:
Company | Acquisition Date | First Invested on | First Round of Investment | Round Size |
|---|---|---|---|---|
Nov 25, 2025 | Nov 08, 2022 | Seed | 9930 | |
Oct 23, 2025 | Jun 28, 2022 | Seed | 9269 | |
Oct 22, 2025 | Aug 10, 2022 | Seed | 2668 | |
Jul 16, 2025 | Feb 27, 2019 | Seed | 2927 | |
May 13, 2025 | Jun 06, 2024 | Series A | 6051 |
Team profile of Castle Island Ventures
Castle Island Ventures has a team of 4 members including 4 Partners located in United States. Castle Island Ventures' team does not sit on the board of any company as of now.Here is a list of all team members in Castle Island Ventures:
Name | Designation | Location | Board Memberships | Contact Details |
|---|---|---|---|---|
Partner | United States | - | - | |
Partner | United States | - | - | |
Partner | United States | - | - | |
Partner | Boston | - | - |
Co-investors of Castle Island Ventures
Over the past 8 years, 723 investors have co-invested in Castle Island Ventures's portfolio companies. This includes funds and angels.
- Invested before Castle Island Ventures: Y Combinator, CMT Digital and 111 others have invested in rounds before Castle Island Ventures. There are 3 companies where Y Combinator has invested before Castle Island Ventures and 2 companies where CMT Digital has invested before Castle Island Ventures.
- Top Co-investors of Castle Island Ventures: 362 investors entered a company along with Castle Island Ventures. These include investors like Coinbase (10 companies).
- Invested after Castle Island Ventures: A total of 248 investors have invested in Castle Island Ventures's portfolio after their investments. Top Investors include Galaxy (5 companies), Coinbase (4 companies) and M13 Company (3 companies).
Recent News related to Castle Island Ventures
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Cyclops Secures $20 Million Series A to Streamline Stablecoin PaymentsRefresh Miami•Jul 15, 2026•Global Paytech Ventures, Cyclops, Circle, Nava Ventures and 2 others
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Valinor Raises $25 Million to Link Blockchain and Private CreditPYMNTS.com•Mar 30, 2026•Valinor, Castle Island Ventures
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X Hires Coinbase Vet Ahead of X Money LaunchPYMNTS.com•Mar 26, 2026•X, Coinbase, XFX, Haun Ventures and 1 other
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Tazapay nets $36m series B led by Circle VenturesStartupNews•Mar 26, 2026•TazaPay, Circle, Arc180, Norinchukin Capital and 11 others
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Remittance start-up Félix Pago bags $15.5m Series A fundingFinTech Futures•Mar 19, 2026•Felix, Castle Island Ventures, Switch
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Cyclops Raises $8M in FundingFinSMEs•Mar 04, 2026•Shift4, Cyclops, Castle Island Ventures, F-Prime Capital
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Alfred raises $15M to streamline global payments in Latin America.Refresh Miami•Feb 19, 2026•F-Prime Capital, Shift4, Cyclops, Castle Island Ventures
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Birch Hill Raises $2.5M Pre-Seed Led by ParaFi Capital, Castle Island VenturesThe Block•Feb 11, 2026•ParaFi, Castle Island Ventures, Birch Hill Equity Partners, FalconX and 5 others
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Post-Quantum Security Startup Project Eleven Secures $20M Series ANftgators•Jan 15, 2026•Projecteleven, Nebular, Fin Capital, Variant Fund and 7 others
