Does the forecast market with monthly turnover of 44.8 billion US dollars need a main broker?
Source: Fintech Blueprint Compiled and edited by BitPushNewsBetterment recently published its 2026 retail investor survey. The main conclusion is that 26% of Gen Z investors see sports betting as part of their long-term financial strategy, and 52% have invested the money they originally intended to invest into it last year. The survey of 1000 US retail investors in early April showed that proportion rapidly declined as people grew older — 31% and 14% for millennials, 10% and 6% for Gen X, and 4% and 1% for Baby Boomers. Betterment CEO Sarah Levy put it bluntly: The problem comes when a prediction market or sports betting platform starts to feel like a retirement strategy. The combined monthly trading volume of Kalshi and Polymarket reached $44.8 billion in June, which is more than three times the average monthly transaction volume of approximately $14 billion for all US legal sports betting in 2025. Source: Bloomberg/Betterment Let's explore whether this transaction volume is huge enough to support the dedicated agency hierarchy below. Earlier this month, River Markets raised $8.5 million in seed funding to build what it calls “the first institutional-grade execution and prime broker platform for the prediction market.” Led by Haun Ventures, Y Combinator, Coinbase Ventures, Qube Research & Technologies, and Cherry Ventures participated, in addition to angel investors from Citadel, HRT, J.P. Morgan, Nvidia, and Google. The company has been online with trading clients since May 1 and has publicly listed five client names: Chimera Capital Management, Game Point Capital, Cleat Street, Skywalk, and 646 Equity. It claims to own three of the top ten traders on Kalshi and Polymarket, as well as several quantitative funds running on its API. The problems they are solving are real and unremarkable. The liquidity of the prediction market is distributed across multiple trading sites, which may have different quotes on the results of the same event, involving separate accounts, separate balances, independent APIs, and no uniform view of risk. A trader who trades the same event on Kalshi and Polymarket actually manually manipulates the two books and then reconcile the accounts. River integrates these sites into a single terminal and an API, uses a unified code system, adds execution algorithms (iceberg orders, linked orders, stop-loss orders, take-profit orders) not native to the exchange, and routes eligible orders to the best prices in the online ledger. It's live on Kalshi, Polymarket, and Polymarket US, and is integrating Novig and Crypto.com. Today, it's more like an order and execution management system than a Prime Broker (PB) — a boundary drawn by River itself. Its FAQ states that the real-time platform covers execution, routing, data, and profit and loss, that customer funds are kept in venue accounts rather than centrally pooled, and that companies are invited to contact them about financing, collateral, and cross-market requirements. Source: Allium predicts that the cumulative historical trading volume of the market exceeded 150 billion US dollars in May. Kalshi alone reached 31.5 billion US dollars in June, while Polymarket was 10.8 billion US dollars. Kalshi is currently in final negotiations to finance at least $750 million, with a valuation of $40 billion; Polymarket is financing at a valuation of $15 billion, after ICE had already committed $2 billion in two instalments. Kalshi's annualized revenue surpassed $4 billion in July, roughly double the $2 billion annualized pace two months ago. At the peak of the World Cup,...
