MCJ (formerly MCJ Collective) is a Boston-based venture capital firm backing early-stage founders driving the transition of energy and industry and solving the inevitable impacts of climate change. The firm closed its second fund at $80.6M and has over $115M in total assets under management.
41% of their portfolio is in Climate & Energy. Their most common stage is seed (43% of deals). Average disclosed round size is $52.7M (across 56 rounds with reported amounts).
Portfolio
54
Fund Size
$80.6M
Top Stage
Seed
Last 12 Mo
5
Team
Portfolio Breakdown
Stage Distribution
Sector Distribution
Investment Activity
DealsAvg Round Size
Portfolio
63 investments
| Company | Round | Amount | Date |
|---|---|---|---|
| OOdyssey Energy | Growth | $74M | Sep 2026 |
 Light Energy | Unknown | $46M | Sep 2026 |
| RRed Metals | Seed | $10M | Jun 2026 |
 Dg Matrix | Series A | $60M | Feb 2026 |
 Avalanche Energy | Series A | $29M | Feb 2026 |
 Reservoir | Seed | $8M | Jan 2026 |
 Zeno | Seed | $25M | Jan 2026 |
 Crusoe | Series E | $1.4B | Oct 2025 |
| RRodatherm Energy | Series A | $38M | Sep 2025 |
 Aalo Atomics | Series B | $100M | Aug 2025 |
 LGND AI | Seed | $9M | Jul 2025 |
 The Nuclear Company | Series A | $51.3M | May 2025 |
 Exowatt | Series A | $50M | Apr 2025 |
 Nitricity | Seed | $10M | Mar 2025 |
 Hammerhead Ai | Seed | $10M | Jan 2025 |
| RRodatherm Energy | Series A | — | Jan 2025 |
 Crusoe | Series E | — | Jan 2025 |
 Heirloom | Series B | — | Dec 2024 |
 Mantel | Growth | — | Sep 2024 |
 VerSe | Series A | $20.5M | May 2024 |
 Airloom Energy | Seed | $12.7M | May 2024 |
 Quilt | Series A | $33M | Apr 2024 |
 Arch | Seed | $6.2M | Feb 2024 |
 Paces | Series A | $11M | Jan 2024 |
 Moment Energy | Series A | $15M | Jan 2024 |
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Top Co-Investors
Lowercarbon Capital21 shared
Breakthrough Energy Ventures8 shared
Fine Structure Ventures7 shared
Congruent Ventures7 shared
Alumni Ventures7 shared
Toyota Ventures7 shared
Founders Fund6 shared
Energy Impact Partners6 shared
Salesforce Ventures5 shared
Valor Equity Partners5 shared
Y Combinator5 shared
Garage Capital5 shared
Activate Venture Partners4 shared
Active Impact Investments4 shared
Collaborative Fund4 shared
Coatue Management LLC4 shared
New Climate Ventures4 shared
Galvanize Climate Solutions3 shared
StepStone Group3 shared
Spark Capital3 shared
Last updated: 7 October 2026