River Markets raises $8.5 million to build prediction-market prime brokerage

River Markets has raised $8.5 million in seed funding to build an institutional execution and prime-brokerage platform for prediction markets. Haun Ventures led the round, with Coinbase Ventures and Y Combinator among the investors. Other backers included Qube Research Technologies and angels from Google, Nvidia, Novig, JPMorgan and Citadel. The company did not disclose the valuation, and Fortune reported that the round closed in July.

The start-up says prediction markets are still fragmented, with liquidity spread across several venues and traders switching between separate interfaces to manage positions on the same event. River argues that this makes risk management harder and hedging less efficient, because users lack a consolidated view across markets.

Its planned product is meant to sit between professional clients and prediction-market exchanges as an execution layer. The offering includes smart order routing, built-in risk controls and a dashboard that shows consolidated positions and profit and loss across Kalshi, Polymarket and Novig. Smart order routing would let clients compare available liquidity and split orders across platforms.

River Markets was founded by Oscar Levy and Antonin Perrot. Levy previously worked in quantitative strategy at BlackRock, and Perrot worked in electronic trading at Morgan Stanley and high-frequency trading at Valkyrie Trading. The two began building trading software for Kalshi and Polymarket in 2023 before turning those tools into a broader institutional product. Levy said the transition from mainstream retail to institutional users cannot be achieved with today's consumer interfaces. 'Somebody needs to make these accessible and familiar for existing institutions,' he said.

Fortune reported that River has been providing software, data links and risk-management tools since launching in May, and that it is on track to exceed hundreds of millions of dollars in annualized trading volume by year-end. CryptoBriefing reported that the company said it had already facilitated more than $50 million in trading volume and supported three of the top 10 traders on both Kalshi and Polymarket.