Rusheen Capital Management

Founders and managing partners Jim McDermott and Jeff Green make all investment decisions. McDermott was the founder and managing director of US Renewables Group, one of the largest clean-energy PE firms in the United States, and a co-founder of Fulcrum Bioenergy. Green was founder, CEO, and board chair of NanoH2O, the largest water-industry exit in the last 15 years. The two have worked together since co-founding Stamps.com in 1996.

The firm uses a company-creation and spin-out model. It originates investments by building de novo companies and acquiring technology from corporate or university labs, rather than through competitive auction processes. That approach leverages the operating experience McDermott and Green gained while founding NanoH2O and Fulcrum Bioenergy.

Rusheen invests in growth-stage companies. Its portfolio ranges from early commercialization plays, such as a carbon capture system for semi-trucks and modular onboard carbon capture for maritime shipping, to industrial-scale developers like the leading global direct air capture facility company.

The firm’s disclosed focus is narrow: carbon capture and utilization, low-carbon energy, and water sustainability. It does not advertise exposure to sectors outside resource efficiency, such as fintech, healthcare, or traditional software, and its portfolio companies uniformly occupy decarbonization and water-technology niches.

Rusheen is a separate firm but directly linked through its founders. Jim McDermott founded US Renewables Group, and Jeff Green founded NanoH2O. Both exits provide the operational track record that shapes Rusheen’s strategy of building and scaling growth-stage resource-efficiency companies.

Rusheen’s website describes only direct private equity investments — de novo companies, corporate and university spin-outs, and direct equity stakes. There is no indication the firm acts as a limited partner in other managers' funds, but in the absence of a formal policy statement, the extent of fund commitments remains unconfirmed.