Financing the Next Generation of Energy Innovation

Our ApproachView Portfolio
Who We Are

A Different Kind of Growth Capital Partner

WindSail Capital provides senior-secured growth financing to established companies advancing energy innovation and sustainability. We partner with businesses that are often underserved by traditional sources of capital, combining deep industry expertise, tailored capital structures, and a hands-on partnership approach to help management teams accelerate growth while minimizing dilution.

01

Deep Sector Expertise

We are among the first dedicated credit investors in energy innovation and climate. Our industry knowledge and extensive relationships allow us to understand specialized businesses and the markets in which they operate.

Investing since 2013
02

Flexible Capital

We design financing around each company’s growth objectives, not a rigid lending formula. Our secured loans can stand alone or complement equity financing, providing capital without unnecessary dilution.

No equity round required
03

A True Growth Partner

Our relationship extends beyond financing. We work closely with management teams, offering strategic insight, industry introductions, and practical support as companies navigate growth and important milestones.

More than capital
Learn more about our approach

Companies We’ve Backed

View full portfolio

Recent News

All news
Get In Touch

Let’s Start a Conversation

Whether you’re a climate tech founder seeking growth capital or part of the broader clean energy ecosystem, we’d love to hear from you.

133 Federal Street, 9th Floor
Boston, MA 02110