Prelude Ventures
Prelude Ventures is a San Francisco climate venture capital (VC) firm that backs early-stage startups across the climate economy. It deploys roughly $2 billion exclusively for the Simons family and invests in energy, mobility, food and agriculture, and carbon removal. Water is one small corner: as of 2026 it has backed 1 water company, Arable, across 2 deals.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
Prelude Ventures is the climate-investing arm of one family's fortune. It deploys roughly $2 billion, by the firm's own 2023 count, exclusively for Nat Simons and Laura Baxter-Simons, the husband-and-wife team who built it; Nat is the son of Renaissance Technologies founder Jim Simons. The couple started with the Sea Change Foundation in 2006 to fund climate philanthropy, then in 2009 stood up Prelude to do with venture capital what grants alone could not: put real money behind the companies that might actually bend the emissions curve.
Prelude runs as an evergreen, single-investor shop, which frees it from the raise-deploy-exit clock most venture firms live by. The dedicated investment team was built out in 2013 under managing directors Gabriel Kra and Tim Woodward, and today spreads its bets across seven sectors: energy, mobility, food and agriculture, carbon management, compute, manufacturing, and the built environment. In September 2025 it added Juan Pablo Soulier, who came to venture from Tesla and Waymo, as a partner.
Prelude is not a water fund, and a newcomer should hold onto that: water is not even one of its seven named sectors. The single water company (don't) Waste Water tracks in Prelude's portfolio is Arable, an in-field sensor business that reads weather and crop health for farmers, which Prelude backed at Series B and again at Series C. It sits under food and agriculture, the closest Prelude's map comes to water, alongside names like Pivot Bio that cut the fertilizer runoff fouling watersheds.
Prelude Ventures is worth watching less for what it does in water than for the gravity it carries around it: a patient, family-backed balance sheet that can write early cheques into hard climate technology and wait out the long build. For water founders, the read is simple: Prelude shows up when a water bet sits inside a bigger climate thesis, the way Arable rode in on agriculture, not because a company waves the water flag.
Water Commitment Score
Compiled from official filings, third-party records, and direct intelligence from investors and founders, in Leviathan · recomputed monthly · as of Jun 2026.
How they invest
Portfolio · 1 water companies
Invests alongside
Highlighted = profiled on (don't) Waste Water.
Frequently asked
- What does Prelude Ventures invest in?
- Prelude Ventures invests in early-stage climate startups across seven sectors: energy, mobility, food and agriculture, carbon management, compute, manufacturing, and the built environment. It is a generalist climate fund rather than a water specialist, and its water exposure comes indirectly, through agriculture and climate-resilience companies like the sensor firm Arable.
- Is Prelude Ventures a water fund?
- Prelude Ventures is a broad climate venture firm, not a water fund. Water is not one of its named sectors. Within the portfolio (don't) Waste Water tracks, Prelude has backed 1 water company, Arable, across 2 deals, reaching it through its food and agriculture thesis rather than a dedicated water mandate.
- Who runs Prelude Ventures?
- Prelude Ventures was founded by Nat Simons and Laura Baxter-Simons, who supply all of its capital. Its investment team is led by managing directors Gabriel Kra and Tim Woodward, who stood it up in 2013, alongside managing directors Mark Cupta and Matt Eggers, partner Juan Pablo Soulier, and principal Katie Clasen.
- How big is Prelude Ventures?
- Prelude Ventures manages roughly $2 billion, according to the firm's own 2023 announcement, all of it the Simons family's capital. Because it deploys one family's money rather than outside funds, Prelude operates as an evergreen platform and does not raise or market traditional named venture funds.
- Where is Prelude Ventures based?
- Prelude Ventures is based in San Francisco, at the Ferry Building, and invests across the United States and beyond. It was established in 2009 by the Simons family as the venture arm of their climate work, complementing the grant-making of their Sea Change Foundation.