River Markets

Prime brokerage for prediction markets

Y CombinatorSpring 2026ActiveFintechTrading

What they do

Problem

Professional traders lack a unified way to access multiple prediction market venues with best execution and centralized trading operations.

Solution

A prime brokerage platform that aggregates major event-contract venues into one account with best execution, portfolio and order management, and a unified API.

Who it's for

Professional prediction market traders and trading firms who need multi-venue access and execution.

Founders

Oscar Levy

Co-Founder

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.

Antonin Parrot

Founder

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.

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