Firms, funds, partners, companies and rounds from sworn filings, firm sites and announcements, kept as a graph with a date and a source on every edge. Facts, inferences and estimates are labelled as such. A fund target is never a close, GAV is never dry powder, and a round size is never an investor’s check.

Firms / Castle Island Management, LLC

Castle Island Management, LLC

Institutional venture firmHingham, MAcastleisland.vcSEC venture capital fund adviser

Castle Island Ventures is a venture capital firm investing in public blockchain startups. Explore our mission and portfolio.

venture manager, reported GAV $542M across 18 vehicles

Importance
48
elevated
Active deployment
55
elevated
Emerging
0
low
Completeness
81
high
Freshness
100
high
Research priority
18
moderate
Identity and regulatory footprint
Headquarters
Boston, MAadviserinfo.sec.gov
Office address
374 CONGRESS STREET, SUITE 301, Boston, MA, 02210adviserinfo.sec.gov
Business phone
508-202-0432adviserinfo.sec.gov
SEC adviser type
exempt reporting adviseradviserinfo.sec.gov
SEC exemption claimed
venture capital fund adviseradviserinfo.sec.govItem 2.B(1): advises solely venture capital funds
Latest Form ADV
Mar 31, 2026
Private funds reported
16 (16 venture capital funds)adviserinfo.sec.gov
Private fund gross assets
$790Madviserinfo.sec.govreported GAV of the funds, the adviser's own number; not fund size, not dry powder
business email
info@castleisland.vccastleisland.vcpublished by the subject
business phone
508-202-0432adviserinfo.sec.govpublished by the subject
Stated thesis versus observed behaviour
13 observed deals
Stated (the firm’s website)
Sectors
crypto
Stages
early
Geography
not stated
Check size
not stated; DFX does not estimate checks from round sizes
Self-described
venture capital
Observed (from deals on record)
Stage at participation
seed 50%series a 50%
Stage at first entry
seed 50%series a 50%
Sectors
unknown 92%Other Technology 8%
lead rate 75%follow-on rate 0%new logos, 12 months 13
Funds and vehicles
18 reported
VehicleTypeVintageLifecycleReported GAVOwnersForm D soldLatest Form D
CIV Opportunity Series Co-Invest I, L.P. - (series 9)SPV or co-invest vehicle2023 adv first reportedActive deployment$9.0M
Mar 29, 2024
5$0Mar 31, 2022
CIV Opportunity Series Co-Invest I, L.P. - (series 8)SPV or co-invest vehicle2023 adv first reportedActive deployment$6.8M
Mar 29, 2024
10$0Mar 28, 2022
CIV Opportunity Series Co-Invest I, L.P. - (series 10)SPV or co-invest vehicle2023 adv first reportedActive deployment$457,713
Mar 29, 2024
3unknownunknown
Castle Island Ventures III, L.P.Fund2022 adv first reportedActive deployment$146M
Mar 29, 2024
153$0Jan 27, 2022
Castle Island Ventures Iii-A, L.P.Feeder or parallel2022 adv first reportedActive deployment$100M
Mar 29, 2024
69$0Jan 27, 2022
CIV Opportunity Series Co-Invest I, L.P. - (series 4)SPV or co-invest vehicle2022 adv first reportedActive deployment$18.8M
Mar 29, 2024
25$0Jul 30, 2021
CIV Opportunity Series Co-Invest I, L.P. - (series 6)SPV or co-invest vehicle2022 adv first reportedActive deployment$7.3M
Mar 29, 2024
13$0Oct 13, 2021
CIV Opportunity Series Co-Invest I, L.P. - (series 7)SPV or co-invest vehicle2022 adv first reportedActive deployment$6.5M
Mar 29, 2024
19$0Dec 22, 2021
CIV Opportunity Series Co-Invest I, L.P. - (series 3)SPV or co-invest vehicle2022 adv first reportedActive deployment$4.6M
Mar 29, 2024
11$0Mar 29, 2021
CIV Opportunity Series Co-Invest I, L.P. - (series 5)SPV or co-invest vehicle2022 adv first reportedActive deployment$2.0M
Mar 29, 2024
70$0Aug 24, 2021
Castle Island Ventures II, L.P.Fund2021 adv first reportedMature$34.5M
Mar 29, 2024
65$0Jun 23, 2020
Castle Island Ventures Ii-A, L.P.Feeder or parallel2021 adv first reportedMature$23.1M
Mar 29, 2024
85$0Jun 23, 2020
CIV Opportunity Series Co-Invest I, L.P. - (series 2)SPV or co-invest vehicle2021 adv first reportedMature$0
Mar 29, 2024
0$0Feb 24, 2021
CIV Opportunity Series Co-Invest I, L.P. - (series 1)SPV or co-invest vehicle2021 adv first reportedMature$0
Mar 29, 2024
0$0Jul 28, 2020
Castle Island Ventures I, L.P.FundunknownUnknown$168M
Mar 29, 2024
93$0Jun 21, 2018
Castle Island Ventures I-A, L.P.Feeder or parallelunknownUnknown$14.3M
Mar 29, 2024
17$0Aug 14, 2018
Castle Island Ventures IV, L.P.FundunknownFundraisingunknownunknown$0Sep 29, 2025
Castle Island Ventures IV Feeder, L.P.Feeder or parallelunknownFundraisingunknownunknown$0Oct 30, 2025
GAV is the gross asset value the adviser reported on Form ADV for the vehicle, never the fund’s committed size and never dry powder. Form D sold is the amount sold as of the latest filing, never a final close.
Investment team
16 current, 0 departed
Investments on record
13 edges, 13 companies, 2 partner-attributed
CompanyRoundRolePartnerRound sizeThis investorDateSource
Acquired By Talosportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Bitwiseportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Félixportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Félix Pagoportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Project 11portfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Project Eleven Seedportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Rippleportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Trmlabsportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
XFXportfolio listingunknownunknownunknownunknownSep 16, 2026Fact Venture organization websites (about, team, portfolio, thesis, news pages)
Cyclops, Inc.Series A · Series Aparticipantunknown$20.0MunknownJul 15, 2026Fact Press release wires (Business Wire, PR Newswire, GlobeNewswire public RSS)
ValinorFunding roundleadSean Judge (confirmed)$25.0MunknownMar 30, 2026Fact Press release wires (Business Wire, PR Newswire, GlobeNewswire public RSS)
Project ElevenFunding roundleadNIC Carter (confirmed)$20.0MunknownJan 14, 2026Fact Press release wires (Business Wire, PR Newswire, GlobeNewswire public RSS)
TesserSeed Round · Seedleadunknown$4.5MunknownOct 21, 2025Fact Press release wires (Business Wire, PR Newswire, GlobeNewswire public RSS)
“This investor” is the amount disclosed for this investor alone; it is unknown unless a source said it. The round size is the whole round.
Co-investors
29 relationships from shared deals, counted for the whole firm
Limited partners
0 disclosed
No LP commitment on record. An LP edge needs a public disclosure with a quote: a pension report (see Limited partners for the plans read), a fund announcement naming the LP, or a Form ADV owner. The fund page carries the LP’s reported performance.
Timeline
20 dated events
  1. Mar 29, 2023
    CIV Opportunity Series Co-Invest I, L.P. - (series 9) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $9,033,971
  2. Mar 29, 2023
    CIV Opportunity Series Co-Invest I, L.P. - (series 10) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $450,000
  3. Mar 29, 2023
    CIV Opportunity Series Co-Invest I, L.P. - (series 8) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $6,832,251
  4. Jan 1, 2023
    Sean Michael Judge joined Schedule A of Castle Island Management, LLC as Managing Member
  5. Mar 31, 2022
    CIV Opportunity Series Co-Invest I, L.P. - (series 6) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $7,279,161
  6. Mar 31, 2022
    CIV Opportunity Series Co-Invest I, L.P. - (series 7) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $6,548,992
  7. Mar 31, 2022
    CIV Opportunity Series Co-Invest I, L.P. - (series 5) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $2,499,843
  8. Mar 31, 2022
    CIV Opportunity Series Co-Invest I, L.P. - (series 3) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $1,503,239
  9. Mar 31, 2022
    Castle Island Ventures Iii-A, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $98,000,000
  10. Mar 31, 2022
    Castle Island Ventures III, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $152,000,000
  11. Mar 31, 2022
    CIV Opportunity Series Co-Invest I, L.P. - (series 4) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $18,820,378
  12. Feb 1, 2022
    Gretchen Marie Mccarey joined Schedule A of Castle Island Management, LLC as Chief Financial Officer
  13. Jul 1, 2021
    Nicolas Elliott Carter joined Schedule A of Castle Island Management, LLC as Managing Member
  14. Mar 11, 2021
    CIV Opportunity Series Co-Invest I, L.P. - (series 2) first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $1,400,000
  15. Mar 11, 2021
    Castle Island Ventures Ii-A, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $20,525,000
  16. Mar 11, 2021
    CIV Opportunity Series Co-Invest I, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $3,000,000
  17. Mar 11, 2021
    Castle Island Ventures II, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $29,775,000
  18. Oct 12, 2018
    Castle Island Ventures I, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $27,350,000
  19. Oct 12, 2018
    Castle Island Management, LLC first filed Form ADV (ERA, venture capital fund adviser exemption)
  20. Oct 12, 2018
    Castle Island Ventures I-A, L.P. first reported on Form ADV by Castle Island Management, LLC (Venture Capital Fund), GAV $2,100,000
Classification history
  1. Sep 15, 2026
    Institutional venture firm (confirmed, 95%, cls-1)
    venture manager, reported GAV $542M across 18 vehicles
  2. Sep 12, 2026
    Institutional venture firm (confirmed, 95%, cls-1)
    venture manager, reported GAV $542M across 17 vehicles
  3. Sep 12, 2026
    Institutional venture firm (confirmed, 95%, cls-1)
    venture manager, reported GAV $542M across 15 vehicles
Evidence
50 observations from 3 sources
Every observation behind this profile, with its source, date and class
FactValueEffectiveClassSource
Why admittedvc_exemption,vc_funds_reportedMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
SEC exemption claimedventure_capital_fund_adviserMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
SEC exemption claimedventure_capital_fund_adviserMar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
SEC adviser typeexempt_reporting_adviserMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
SEC adviser typeexempt_reporting_adviserMar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
First Form ADV filing2018-10-12Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Adv history loadedadv-hist-1Sep 12, 2026FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Latest Form ADV filing2026-03-31Mar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Latest Form ADV filing2024-03-29Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
SEC statusERA - ActiveMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
SEC status effective2018-10-12Mar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Venture share of reported funds1Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Business phone508-202-0432Mar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Business phone508-202-0432Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Contact page urlhttps://castleisland.vc/contact/
contact page linked from the home page
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
DescriptionCastle Island Ventures is a venture capital firm investing in public blockchain startups. Explore our mission and portfolio.
meta description
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
DescriptionCastle Island Ventures is a venture capital firm investing in public blockchain startups. Explore our mission and portfolio.
meta description
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
HeadquartersBoston, MAMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
HeadquartersHingham, MAMar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Office address374 CONGRESS STREET, SUITE 301, Boston, MA, 02210Mar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Office address350 LINCOLN STREET, SUITE 2400, Hingham, MA, 02043Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Self-described typeventure_capital
We are a venture capital firm
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Self-described typeventure_capital
We are a venture capital firm
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Legal formLimited Liability CompanyMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Legal formLimited Liability CompanyMar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Portfolio pagehttps://castleisland.vc/portfolio/
12 entries read
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Portfolio pagehttps://castleisland.vc/portfolio/
12 entries read
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Private funds reported16Mar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Private funds reported16Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Private fund gross assets (reported)$790MMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Private fund gross assets (reported)$542MMar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Stated sectorscrypto
sector words on the home page
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Stated sectorscrypto
sector words on the home page
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Stated stagesearly
stage words on the home page
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Stated stagesearly
stage words on the home page
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Team pagehttps://castleisland.vc/team/
10 name/title pairs read
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Team pagehttps://castleisland.vc/team/
10 name/title pairs read
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Venture funds reported16Mar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Venture funds reported16Mar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Websitehttp://www.castleisland.vcMar 31, 2026FactSEC Form ADV monthly roster (registered + exempt reporting advisers)
Websitehttp://www.castleisland.vcMar 29, 2024FactSEC Form ADV filing data 2011 to 2024 (every filing, Schedule D 7.B.(1) private funds, Schedules A/B)
Site titleHome - Castle Island Ventures
title tag
Sep 16, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)
Site titleHome - Castle Island Ventures
title tag
Sep 15, 2026FactVenture organization websites (about, team, portfolio, thesis, news pages)