United States · Investor

MCJ

Last cheque observed Sep 2026; 47 cheques on record.

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Deploying nowNew fund $68M, Jan 2024VC firm

SeedSeries AEnergyClimateIndustrial

Deploying now
94%of best year16cheques in 12 months, 47 on record
Since the last cheque60days00hrs00min00sec
Median round$9.0MRounds led0 of 47Sole investor1 roundsMostly inUnited States, 83%
Pitch MCJ

MCJ highlights

  1. 01

    16 cheques in the last 12 months

  2. 02

    Mostly Seed and Venture: 60% of its rounds

  3. 03

    Sole investor in 1 rounds, median $2.0M

What they do

We back founders rewriting industries for the future.From their own website
Type
VC firm
Cheque size
Not stated
Stages
SeedSeries A
Sectors
EnergyClimateIndustrial
Based in
Boston, United States
Cold pitches
Not stated

The record

Every round we can evidence, newest first47 appearances

  1. 2026

    14 rounds

  2. Sept
    OdysseyDebt · US$47MWith 4 others
  3. Sept
    LightSeries A · US · TechStartups$46MWith 11 others
  4. Aug
    ReservoirSeed · US · TechCrunch$8.0MWith 2 others
  5. Jul
    Clean Crop TechnologiesVenture · US$7.9MWith 2 others
  6. Jul
    Rodatherm EnergyGrant · US$8.0MWith 2 others
  7. Jun
    Red MetalsSeed · US · Ventureburn$10MWith 3 others
  8. Jun
    VerseSeries B · US$54MWith 4 others
  9. May
    Moment EnergySeries B · CA$3.0MWith 2 others
  10. May
    RecheckPre-seed · US$2.0MSole investor
  11. Apr
    ClarasightSeries A · US$12MWith 6 others
  12. Apr
    Impossible MetalsVenture · USUndisclosedWith 3 others
  13. Feb
    DG MatrixSeries A · US · TechCrunch$60MWith 8 others
  14. Feb
    ArchimetisVenture · US$12MWith 2 others
  15. Jan
    SensesemiSeed · US$2.7MWith 2 others
  16. 2025

    8 rounds

  17. Dec
    Unlimited IndustriesSeed · US$12MWith 4 others
  18. Nov
    OverstorySeries B · NL · Blume Equity$43MWith 11 others
  19. Oct
    Kodama SystemsSeed · US$7.0MWith 4 others
  20. Aug
    Aalo AtomicsSeries B · US · TechCrunch$100MWith 15 others
  21. Jul
    LGNDSeed · US$9.0MWith 3 others
  22. May
    RhizomeSeed · US$6.5MWith 2 others
  23. Apr
    FourierSeries A · US$19MWith 1 other
  24. Jan
    Moment EnergySeries A · CA · Audacy$15MWith 9 others
  25. 2024

    9 rounds

  26. Dec
    Artyc PBCVenture · USUndisclosedWith 4 others
  27. Oct
    Energetic CapitalVenture · USUndisclosedWith 4 others
  28. Oct
    AirLoom EnergySeed · US$7.5MWith 3 others
  29. Sept
    MantelSeries A · US$30MWith 2 others
  30. Jul
    PacesSeries A · US$11MWith 6 others
  31. Jun
    WaterplanGrant · US$150KWith 4 others
  32. Feb
    Lilac SolutionsSeries C · US$145MWith 4 others
  33. Feb
    ArchSeed · US$6.2MWith 2 others
  34. Feb
    CirplusVenture · DEUndisclosedWith 4 others
  35. 2023

    6 rounds

  36. Oct
    Yard StickVenture · USUndisclosedWith 4 others
  37. Sept
    OpnaSeed · GB$6.5MWith 4 others
  38. Apr
    Phuc LabsVenture · USUndisclosedWith 2 others
  39. Apr
    EvergrowSeed · US$7.0MWith 4 others
  40. Apr
    HelioSeed · GB$3.3MWith 6 others
  41. Mar
    LunSeed · DK$11MWith 4 others
  42. 2022

    6 rounds

  43. Sept
    KopperfieldSeed · US$5.0MWith 4 others
  44. Sept
    Cloud to StreetSeries A · US$12MWith 3 others
  45. Jun
    RheaplyVenture · US$20MWith 5 others

An announcement gives the size of the round, not the size of this investor's cheque: the only rounds that imply a cheque are those where they were the sole named investor.

The team

Named by the firm itself, on a filing, its Form ADV or its company registration5 named

DBDavid B AronoffManaging Member of the General PartneriFiling they signed
JJJason JacobsManaging Member of the General PartneriFiling they signed
JCJustin Cody SimmsManaging Member of the General PartneriFiling they signed
TNThai NguyenManaging Member of the General PartneriFiling they signed
YLYin LuManaging Member of the General PartneriFiling they signed

We also hold 6 people at this firm from the lists this database was built from: a weaker source than the filings, since a list does not say when a title ended. Login to see them.

What the register says

From the firm's own filings with the SEC, which it must file accurately by law

$85Mgross assets of its fundsOct 2026
Exemptreporting adviserventure or small private funds
Legal name
MCJ Management, L.P.
SEC number
CRD 310880

What they claim to have backed

From their own portfolio page (on their website)

0 of 2 we have independently watched raise

Events ↗Mcj

Weaker than a round we watched, stronger than a list somebody sold us. A firm is far less willing to put a company on its own site that it never funded.

Who they invest alongside

The investors most often in the same rounds as MCJ. A count of rooms they were both in, not a relationship either has claimed.

Lowercarbon CapitalVC firm8rounds togetherLiquid 2 VenturesVC firm5rounds togetherPowerhouse VenturesVC firm5rounds togetherTechstarsVC firm5rounds togetherAlumni VenturesVC firm4rounds togetherClimate CapitalVC firm4rounds togetherAndreessen HorowitzVC firm3rounds togetherBreakthrough EnergyVC firm3rounds togetherCoatueVC firm3rounds togetherCongruent VenturesVC firm3rounds togetherEngine VenturesVC firm3rounds togetherPale blue dotVC firm3rounds together

Recently backed

The latest companies MCJ put money into.

Odyssey$47M · Sept 2026Light$46M · Sept 2026Reservoir$8.0M · Aug 2026Red Metals$10M · Jun 2026Moment Energy$3.0M · May 2026Recheck$2.0M · May 2026

Quick answers about MCJ

What does MCJ invest in?

MCJ invests most often at Seed and Venture (60% of the rounds on record), in sectors such as Energy, Climate and Industrial.

How active is MCJ?

47 investments on record, 16 of them in the last 12 months. The most recent was in Sept 2026.

What has MCJ invested in recently?

Its most recent investments on record: Odyssey (Debt, Sept 2026), Light (Series A, Sept 2026) and Reservoir (Seed, Aug 2026).

How big are MCJ's cheques?

The median round it joins is $9.0M.

Does MCJ lead rounds?

Rarely, if at all: none of its 47 investments on record names it as the lead.

Where does MCJ invest?

Most of the companies it backs are in the United States (83%), Canada (5%) and the United Kingdom (5%).

Is MCJ investing now?

Yes: it is actively investing, with 16 investments in the last 12 months.

Who does MCJ invest alongside?

Most often Lowercarbon Capital (8 rounds together), Liquid 2 Ventures (5 rounds together) and Powerhouse Ventures (5 rounds together).

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Built from the rounds we watched, its filings and its own website, refreshed every night. How we count · Report a correction · Is this your firm? Claim it