River Markets

Active

Prime brokerage for prediction markets

Spring 2026Founded 20262 peopleSan Francisco, CA, USA

www.rivermarkets.com ↗LinkedIn ↗X ↗See on the Idea Map Fintech momentum

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Prediction Market BrokerageTransactionalProfessional traders, hedge funds, market participantsLow competition

Moat

Unified API across fragmented venues; execution optimization; professional trader relationships.

Key risk

Prediction market adoption slower than expected; regulatory crackdowns; low-margin transaction business.

Why now

Multiple prediction market venues launching; professional traders need portfolio and order management.

Competitors

Emerging space, direct venue access, Manual aggregation

About

River Markets is the prime brokerage for prediction markets. We aggregate every major event-contract venue into one account, giving professional traders best execution, portfolio and order management systems, and a unified API.

From their website

as of Jun 7, 2026www.rivermarkets.com ↗

SaaSSubscription

River Markets is a prime brokerage platform for prediction markets, enabling professional execution across multiple venues from a single interface. It provides a consolidated trading terminal, advanced order types, and unified risk/position management for desks trading across Kalshi, Polymarket, and related venues.

A unified trading platform that offers a multi-book view, fast execution and risk tooling, and cross-venue order management. Key features include: native execution technologies with iceberg, peg, take-profit and stop-loss orders (managed by River), basket smart routing across exchanges for price improvement, a unified OMS to place/edit/cancel across venues, subaccounts for strategy isolation, and a REST/WebSocket API with a Python SDK for integrated programmatic trading. The platform supports live market data, real-time P/L attribution, and server-side complex orders (Iceberg, Peg, TP/SL) with river_ids mapping contracts to a cross-venue identifier.

Who it’s for: professional trading desks and market-making teams operating prediction-market desks and seeking integrated cross-venue execution and risk management

Features

multi-book trading view
native order types (iceberg, peg, TP/SL)
360° market view across exchanges
unified order management system
subaccounts with per-subaccount P/L
smart routing for best price across venues
REST + WebSocket unified API with SDKs

backed by Y Combinator; mentions of book a demo and early access; references to research/docs and platform launch/existing integrations

Founders · 2

Oscar LevyCo-Founder

Berkeley

Co-Founder at River Markets. Previously quant at BlackRock managing models trading $6B, Sandbar Asset Management ($2B AUM hedge fund). MA Financial Engineering from UC Berkeley.

LinkedIn ↗

Antonin ParrotFounder

Co-founder of River Markets, the prime broker for prediction markets. I have a background in engineering and CS, and I've been working as a quant at a high frequency option market making trading shop.

LinkedIn ↗X ↗

Launch · 1 launch

River Markets - The prime broker for prediction markets · May 2026
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River Markets allows funds and pro traders to focus on alpha by handling their execution and trading infrastructure
River Markets provides institutional trading infrastructure for prediction markets. The platform offers smart order routing across exchanges, advanced execution tools, and a unified API for traders to access liquidity across venues.
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Formerly “Centos Group” · why startups rename →

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