Pew Research: Prediction Market Volume Doubled May-July, Sports Now Largest Category
Pew Research Centre published an analysis on September 23 finding that combined monthly trading volume on Kalshi and Polymarket doubled from $26 billion in May to $53 billion in July 2026, driven by sports contracts. Sports is now the largest category on both platforms. The FIFA World Cup drove Kalshi to $58 billion in monthly sports volume in June-July. Americans wagered roughly $40 billion at licensed sportsbooks in Q1 2026 — roughly matching prediction market sports volume in the same period.
The Pew Research Centre published an analysis on September 23 documenting the acceleration of prediction market trading through summer 2026. Combined monthly global trading volume on Kalshi and Polymarket rose from $26 billion in May to $53 billion in July — a doubling in two months — driven primarily by sports contracts. The FIFA World Cup in June and July generated Kalshi's largest sports volumes to date: $58 billion in monthly sports contract volume in the World Cup months, and Polymarket nearing $22 billion. Pew noted that prediction market volume has quadrupled over the past two years. This is the first major independent research institution to quantify the sector's growth with platform-level data.
For UK readers, the relevant comparison is with the UK's regulated betting exchanges and sports betting market. The UK gambling market — one of the world's largest per capita — processes roughly £12 billion in annual sportsbook gross gaming revenue. Prediction market sports volume, now exceeding $50 billion per month, is a different measure (traded contract value rather than net stakes), but the scale comparison illustrates that the US prediction market sports sector has grown to rival or exceed the largest regulated gambling markets in the world in terms of total financial flow through the system. The Gambling Commission, which does not currently regulate US prediction markets, is monitoring whether EU-accessible platforms create any exposure for UK-licensed operators — a question that has not yet produced enforcement action but is under review.
The comparison with US licensed sportsbooks is the Pew report's most policy-relevant finding. Americans wagered approximately $40 billion at legal sportsbooks in Q1 2026 — roughly matching prediction market sports trading volume in the same period. The two measures are not directly comparable (sportsbook handle is total wagered; prediction market volume is total contract value traded), but the order-of-magnitude similarity supports the state AGs' argument that prediction market sports contracts serve overlapping demand with licensed sports gambling products. For a state AG trying to demonstrate harm to the licensed sports betting industry — which pays significant licensing fees and taxes — the Pew volume data is useful evidence that prediction markets are diverting economically significant activity from the licensed framework.
Pew's separate finding on trader profitability is notable: most prediction market sports traders break even or post small losses across nearly 12,000 accounts analysed. The finding weakens the gambling harm argument (the loss distribution is different from a casino product where most participants lose) and subtly complicates the wisdom-of-crowds claim (if most participants break even, the aggregate probability accuracy may be driven by a small number of sophisticated traders rather than broad-based collective forecasting). Neither finding is dispositive in the legal debate — CFTC's preemption argument does not depend on whether traders profit — but both are useful data points for calibrating the policy discussion in terms of actual economic outcomes rather than theoretical harms.
Operators mentioned in this article
Recent updates
Kalshi Suspends Congressional Candidate for Trading on Own Race — Senate Already Banned Members
Kalshi suspended North Carolina candidate Laurie Buckhout for three years on August 31 for trading on her own congressional race — the first known candidate enforcement action. A broader Kalshi investigation found multiple politicians trading on their own races including George Santos. The Senate unanimously banned members and staff from prediction market trading on April 30. A CNN feature on September 24 documents election officials' concerns about disinformation and insider trading risk as the 3 November midterms approach.
Democrats Now 60% Senate, 90% House Favourites on Prediction Markets — Biggest Shift Since 2024
Kalshi and Polymarket have moved sharply toward Democratic control of both US congressional chambers ahead of the 3 November midterms. Democrats are priced at ~60% to win the Senate and ~90% to win the House. Republicans held 80%+ Senate control odds when markets opened in November 2024. The shift started in February 2026 with the Iran war and has accelerated with rising gas prices and declining Trump approval ratings.
SCOTUS September 28 Long Conference: First Opportunity to Take the Prediction Market Case
The Supreme Court's September 28 'long conference' — its first sitting of the new term — is the first formal opportunity for justices to consider cert petitions from New Jersey (filed 2 Sep, Third Circuit) and Robinhood (filed 9 Sep, Ninth Circuit). Kalshi has 30 days to respond to NJ's petition. Polymarket prices a 46% chance SCOTUS accepts by year end. Most analyst projections place a cert decision between November and December 2026.