Rainmatter
Rainmatter is the venture and grant-making arm of Zerodha, India's largest stockbroker, backing fintech, climate and health startups from a 1,000 crore rupee perpetual fund. In water it has backed 2 companies, from wastewater recycling to AI water-monitoring. As of 2026 it invests patient capital with no exit deadline.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
Rainmatter is the unusual case of a stockbroker that decided to become a patient investor. Zerodha, the firm that turned India onto cheap online trading, plows its own profits into Rainmatter, a 1,000 crore rupee (about 120 million dollars) perpetual fund that backs founders in fintech, climate and health and never has to sell. There are no outside limited partners and no exit deadline, which is about as far from a normal venture fund as you can get.
Rainmatter's climate book is where water lives. Across roughly 43 climate-tech investments, the team works to a stated 10 to 15 year time horizon spanning agriculture, energy, waste and water, of which just 2 are pure water plays in the Leviathan database. That long lens is the whole point, because water infrastructure in India pays back slowly, and a fund with no clock can afford to wait for it.
Rainmatter's 2 water bets sit at opposite ends of the same problem. Boson Whitewater takes the treated effluent a city already flushes away and turns it back into drinking-grade water; FluxGen builds the software layer, an AI platform that tells factories and campuses where their water is quietly leaking. Both are bets on water you already have rather than new water, which fits a country where the cheapest litre is the one you never wasted.
Rainmatter does not stop at the fund. Alongside it sits the Rainmatter Foundation, which has committed 200 million dollars in grants to forests, soil and water under the line "a little more forest, everywhere". For a founder, that is the tell. Rainmatter is the rare backer that can fund a slow water company with patient capital and a grant arm from the same building, and is in no hurry to ask for the money back.
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 · 2 water companies
Invests alongside
Highlighted = profiled on (don't) Waste Water.
Frequently asked
- What does Rainmatter invest in?
- Rainmatter invests in early-stage Indian startups across fintech, climate, health and storytelling, the four themes Zerodha cares about. Rainmatter backs founders from a 1,000 crore rupee perpetual fund, and within climate it has funded roughly 43 companies, 2 of them water businesses tracked by (don't) Waste Water.
- Who runs Rainmatter?
- Rainmatter is led by Dinesh Pai, who heads its investments, and was set up by Zerodha founder Nithin Kamath. Rainmatter's climate and environment grant-making runs through the Rainmatter Foundation under chief executive Sameer Shisodia, rather than through a traditional team of general partners chasing quick fund returns.
- Does Rainmatter invest in water?
- Rainmatter does invest in water, as one strand of its climate portfolio. Rainmatter has backed 2 water companies in the Leviathan database: Boson Whitewater, which recycles treated sewage into drinking-grade water, and FluxGen, whose software helps large sites track and cut their water use. (don't) Waste Water rates its water commitment Committed.
- Is Rainmatter a venture capital fund?
- Rainmatter works like a venture capital fund but with an unusual structure. Rainmatter is a 1,000 crore rupee perpetual fund, meaning it invests Zerodha's own profits as patient capital with no fixed exit deadline, unlike traditional funds that must return money to outside investors within seven to ten years.
- Is Rainmatter part of Zerodha?
- Rainmatter is an initiative by Zerodha, India's largest stockbroker, not a separate firm, and is funded from Zerodha's own balance sheet. Rainmatter by Zerodha is also distinct from unrelated companies that share the name, including a London health-tech business, so check for the Zerodha link when searching.