Prediction Markets Hit $50.6B in July, Driven by World Cup Activity

Prediction markets smashed records in July, logging $50.6 billion in taker notional trading volume across Kalshi, Polymarket and Polymarket US — the highest monthly total yet, according to data published Aug. 3. Key figures and context - July volume: $50.59 billion (up 7.8% from a revised June total of $46.95 billion). - Platform breakdown: Kalshi led with $37.7 billion (~74.5% of the total). Polymarket’s two venues produced a combined $12.9 billion: Polymarket US $5.0 billion (up 54% month-over-month) and Polymarket international $7.9 billion (down 26%). - The metric is taker notional volume — a measure of contract turnover — not customer deposits or platform revenue. A single dollar can be counted multiple times if a contract changes hands, so the headline total reflects liquidity and trading activity rather than new capital or income. Notes on data revisions and platform dynamics - The July surge follows a revision to June’s numbers. The Block initially reported $44.8 billion across the three venues but later raised June’s baseline to $46.95 billion after additional data arrived. - Polymarket US’s rapid growth coincides with its broader rollout after removing an app waitlist in May and its designation by the CFTC (QCX). Kalshi has held the same federal designated contract market status since November 2020. - While Polymarket US gained activity as Polymarket international fell, monthly totals can’t prove individual traders migrated between platforms. Rutgers statistician Harry Crane has estimated that roughly 30% of Polymarket’s offshore volume could come from U.S. users (range 19%–48%), but blockchain data can’t definitively locate traders. World Cup’s outsized role - The FIFA World Cup, which ran June 11–July 19, drove a wave of quickly settling sports contracts. Kalshi’s market on the final (Spain vs. Argentina) alone handled about $1.89 billion in volume; Spain won 1–0. - Chainalysis separately estimated that on-chain World Cup prediction markets generated about $20 billion from January through the tournament’s end. During the five-week competition roughly 400,000 wallets produced $5.7 billion, and World Cup markets made up about 63% of prediction-market activity in that period. - Those Chainalysis figures (on-chain-only) are not directly comparable to The Block’s dataset, which combines Kalshi’s centralized trading with Polymarket’s venues. Open interest and settlement trends - Open interest across Kalshi and both Polymarket platforms fell from roughly $2 billion at the start of July to about $1.2 billion by month-end, reflecting widespread contract settlement as the World Cup concluded even as monthly turnover hit record highs. Regulatory backdrop - The record came amid active legal battles over whether federal derivatives rules pre-empt state gambling enforcement. On July 31, New York sued Kalshi alleging it operated an “illegal, unlicensed gambling operation,” seeking injunctions, fines and restitution (allegations have not been adjudicated). - Four days earlier, a federal judge in Minnesota temporarily barred the state from enforcing its prediction-market law against Kalshi and Polymarket US, finding the platforms were likely to succeed on part of a federal-preemption claim. The court cautioned that not every event contract necessarily qualifies as a federally regulated swap and left open the scope of any permanent relief. The injunction allows both platforms to continue operating while litigation proceeds. What’s next August will be the first full month without the World Cup tailwind. Observers will be watching whether sports, political and economic event markets can sustain the record trading pace amid continuing legal uncertainty in key U.S. states.