The one constant about event contracts in 2026 is that everyone is trying to get into the sector, whether as a market exchange or as a provider of tools for users.
River Markets has now closed an $8.5 million seed round, strengthening its push to simplify professional access to event contracts. Led by Haun Ventures and closed in July, the round drew support from Y Combinator, Coinbase Ventures, Qube Research & Technologies, and angel investors connected to Google, Nvidia, Novig, JPMorgan, and Citadel. So, basically all of Silicon Valley.
The founders left the valuation undisclosed, citing early results that already include more than $50 million in trading volume and 200% week-over-week growth between April and July.
Oscar Levy and Antonin Parrot launched the platform on May 1 after building trading software for existing venues and generating seven-figure profits on their own. Several of the highest-volume traders and multiple quant funds now rely on the system internally. Levy said the company is on track to reach hundreds of millions of dollars in annualized volume by year-end, driven by demand for tools that let institutional trading desks move size without juggling separate accounts and risk systems.
Solving Liquidity Fragmentation with Unified Execution
Event contracts start with near-zero resting liquidity and must rebuild depth for every new market. Professional traders therefore face scattered order books, idle capital across platforms, and slow onboarding that can take months. River Markets counters this by offering a single connection that scans available depth, routes orders intelligently, and displays consolidated positions and P&L. An event-contract portfolio helper, if you will.
The platform currently links Kalshi, Polymarket, Polymarket US, and Novig. A unified asset ID system lets clients write integration code once, while historical order-book data and advanced order types- icebergs, pegs, stop-losses, and take-profits flow through both the terminal and API. Algorithms dynamically adjust aggression so larger tickets create less market impact. Levy noted that current consumer interfaces cannot support institutional workflows, which is why the team focused on familiar, high-performance execution.
Haun Ventures investor Mark Beylin highlighted the founders’ dual perspective. They know the daily frictions traders face and apply experience gained building systems for multi-billion-dollar portfolios. The firm published a post comparing the present moment to the early days of listed options, when fragmentation first required specialized infrastructure.
Quant Background Powering Practical Design
Levy and Parrot met as students at UC Berkeley. Levy later became a vice president of quantitative strategy at BlackRock. Parrot worked in electronic trading at Morgan Stanley before joining the high-frequency team at Valkyrie Trading. Their internal tools, created in 2023 to avoid lengthy exchange integrations, evolved into the full River Markets product.
Early users already rank among the largest volume generators on the connected venues. The founders continue refining the system with direct feedback from these desks, prioritizing speed, security, and capital efficiency. Having traded the markets themselves, they designed features that remove operational bottlenecks rather than theoretical ones. We are clearly seeing a modern movement in tech and markets, as more and more engineers become personally involved in mastering markets by developing advanced toolsets drawn from their own experience in the finance industry.
The $8.5 million will expand the engineering team, accelerate system performance, and harden security. Sales and operations capacity will grow as more professional clients come online. Execution and risk modules are already live; the next phase focuses on models that enable firms to deploy capital more efficiently and trade at greater scale.
Institutional volume has risen sharply elsewhere across prediction markets. Kalshi previously reported an 800% increase over six months as block trades have appeared for carbon-allowance and GPU-rental exposures. Yet operational friction and obstacles still limit broader participation. River Markets seeks to remove that friction by presenting a single institutional-grade interface.
Levy and Parrot view event contracts as an emerging global asset class that will mature only when it receives the same execution standards found in every major market. The new funding gives them the runway to deliver that layer and test whether early momentum can convert into sustained institutional adoption.
References
- Exclusive: River Markets announces $8.5 million seed round to build prediction market trading tools for institutions
- River Markets Raises $8.5M to Build the First Prime Broker for Prediction Markets
- River Markets: Prime brokerage for prediction markets | Y Combinator
- The Execution Layer for Prediction Markets: River Markets
- Announcing Our $8.5M Seed Round
- Haun Ventures announcement post
- River Markets funding announcement post
The PolyPunter staff works tirelessly to bring you the latest and most insightful news, information, and tips on the fast-growing economic, financial, and social phenomenon that is prediction markets.
