WindSail Capital Group is a Boston-based investment firm providing growth financing to companies advancing energy innovation, climate technology and sustainability across a wide range of industries.
We partner with founders and management teams who are scaling commercial businesses across the energy transition, offering a flexible, less dilutive alternative to traditional equity.
WindSail is among the first dedicated credit investors in energy innovation and climate, and our portfolio has spanned a wide range of business types, industries, sectors and geographies.
A True Growth Partner, Not Just a Financial Offering
Deep familiarity with the energy transition ecosystem and the operating realities of early-growth climate companies.
Strategic guidance, financial support and introductions through the inflection points that matter, without governance overhead.
Built on speed, flexibility and follow-through. CEO references available in diligence.
What We Believe
The energy sector is dynamic. We build flexibility into every transaction, because rigid lending doesn’t serve innovative companies.
Over a decade investing exclusively in energy and climate tech gives us depth that makes us better partners.
Less dilutive capital, deployed thoughtfully, is one of the most powerful tools available to climate tech founders.
Structured Around Your Needs
Investment Criteria
Seeking growth capital?
If you’re a growth-stage clean energy company seeking less dilutive capital, we’d like to learn more.