River Markets raises $8.5M seed round to build Wall Street-grade tools for prediction markets

Prediction markets have spent the last couple of years graduating from niche curiosity to legitimate financial infrastructure. River Markets, a San Francisco-based startup, just raised $8.5M in seed funding to accelerate that transition by giving hedge funds and prop trading firms the kind of execution tools they’re used to in traditional markets.

The round was led by Haun Ventures, with participation from Y Combinator, Coinbase Ventures, and institutional backer Qube Research Technologies. Angel investors from Google, Nvidia, Novig, JPMorgan, and Citadel also chipped in. The round closed in July.

A prime brokerage for event contracts

River Markets is essentially building the prime brokerage layer that prediction markets never had. The platform aggregates access to multiple venues, including Kalshi, Polymarket, Polymarket US, and Novig, into a single account. The feature set includes smart order routing, iceberg orders, advanced order types, and unified portfolio management across venues.

The company says it has already facilitated over $50M in trading volume. It also claims to support three of the top 10 traders on both Kalshi and Polymarket.

The fragmentation problem River Markets is solving is real. Professional traders currently need separate accounts on each venue, each with its own interface, order types, and risk management tools. River Markets consolidates all of that.

The founders’ quant finance pedigree

Co-founders Oscar Levy and Antonin Parrot bring the kind of resumes that make institutional investors comfortable writing checks. Levy, who serves as CEO, previously worked as a quantitative analyst at BlackRock, where he managed models covering $6B in notional value. Parrot, the CTO, has a background in quantitative trading at high-frequency firms.

Qube Research Technologies is a quantitative trading firm. The angel investors from Citadel and JPMorgan aren’t writing checks because they think prediction markets are a fun hobby.

Why institutions care about prediction markets now

Kalshi, which operates as a CFTC-regulated exchange, has been the most visible player pushing prediction markets toward mainstream financial acceptance. Polymarket, built on crypto rails, has attracted significant volume, particularly around political and macro events. But neither platform alone offers the cross-venue execution layer that professional traders need.

The participation of Coinbase Ventures in this round is notable for another reason. Polymarket operates on the Polygon blockchain, and much of the prediction market volume flowing through crypto-native venues relies on on-chain settlement. A platform that bridges regulated venues like Kalshi with crypto-native ones like Polymarket needs to navigate both worlds.

Polymarket attracted massive volume during the 2024 US presidential election cycle, demonstrating that these markets can generate institutional-level liquidity around major events.