Pew Research: Prediction Market Volume Doubled May-July, Sports Now Largest Category
A Pew Research Center analysis published September 23 found that combined monthly trading volume on Kalshi and Polymarket more than doubled from May to July 2026 — rising from $26 billion in May to $53 billion in July — driven primarily by sports contracts. Sports is now the largest trading category on both platforms. During the FIFA World Cup in June and July, Kalshi's monthly sports volume reached $58 billion. Over the same period, Americans wagered roughly $40 billion at licensed sportsbooks — suggesting prediction market sports volume has approached or exceeded licensed sports betting in dollar terms.
The Pew Research Center published an analysis on September 23, 2026 documenting the acceleration of prediction market trading volume through the summer. 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 — with sports contracts identified as the primary driver of the increase. Sports is now the largest trading category on both platforms by a substantial margin. The FIFA World Cup, held in June and July 2026, generated particularly high volumes: Kalshi's monthly sports volume hit $58 billion in the World Cup months, and Polymarket's sports volume neared $22 billion in the same period. Pew noted that prediction market volume has quadrupled over the past two years. The analysis is the first major independent research institution study to quantify the scale of the sector's growth with platform-level data.
The comparison with licensed sports betting is the most striking data point in the Pew report. Americans wagered approximately $40 billion on legal sportsbooks in the first quarter of 2026 — roughly on par with the combined prediction market trading volume on sports over the same period. If monthly sports prediction market volume holds at July's level for the rest of 2026, the annual total would exceed licensed sportsbook handle by a substantial margin. That comparison is not precise — prediction market 'volume' is the value of contracts traded, while sportsbook 'handle' is the total wagered, and the two measure different things — but the order-of-magnitude similarity is significant for the policy debate over whether prediction market sports contracts are a materially different product from sports gambling. State AGs have argued they are functionally equivalent; the volume comparison provides circumstantial evidence that the markets serve overlapping demand, even if the legal and product structures differ.
The Pew analysis does not break down volume by platform in detail, but the data is consistent with Kalshi's continued market share dominance. Kalshi reported $14.1 billion in weekly volume during NFL kickoff week in September — 92% of combined Kalshi-Polymarket sports contract volume — and if May's $26B combined total already included World Cup ramp-up, Kalshi was likely generating the substantial majority of that sum. Pew's finding that sports is now the largest trading category on both platforms is particularly notable given Kalshi's and Polymarket's origins as political and economic prediction tools. Sports has overtaken elections and macroeconomic markets as the primary volume driver — a shift that was essentially complete by the start of the 2026 NFL season and that has direct regulatory implications: the state-AG enforcement campaign is specifically targeting sports contracts, which are now the economic core of both platforms.
A separate Pew finding deserves attention: most prediction market sports traders break even or post small losses, based on Pew's analysis of nearly 12,000 trading accounts. The finding challenges both the 'gambling harm' narrative advanced by state AGs (if most participants are breaking even, the distribution of losses is different from a lottery or casino product where the house edge is substantial) and the 'superior forecasting' narrative advanced by platforms (if most traders are not profiting, the market's aggregate probability accuracy may be driven by a small number of sophisticated traders rather than broad wisdom-of-crowds effects). For the regulatory debate, the profitability distribution matters: a product where most participants break even or post small losses is structurally different from a product where most participants lose significant sums, and the harm justification for state prohibition is weaker if the empirical loss profile is modest.
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Kalshi Suspends Congressional Candidate for Trading on Own Race — Senate Already Banned Members
Kalshi disclosed on August 31 that it suspended North Carolina congressional candidate Laurie Buckhout for three years and fined her $2,589 for trading on her own race — the first publicly known enforcement action against a candidate for prediction market insider trading. Kalshi said it found multiple politicians trading on races they were involved in, including former Congressman George Santos. The Senate had unanimously banned its members and staffers from prediction market trading on April 30. CNN published a major feature on September 24 documenting election officials' concerns about disinformation and insider trading risk from prediction markets as the midterms approach.
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SCOTUS September 28 Long Conference: First Opportunity to Take the Prediction Market Case
The Supreme Court's September 28 'long conference' — the Court's first conference of the new term — is the first opportunity for the justices to consider whether to grant certiorari in the prediction market cases currently on the docket. New Jersey filed its petition on September 2 (from the Third Circuit loss); Robinhood filed on September 9 (from the Ninth Circuit loss). Kalshi has 30 days to respond to the New Jersey petition. Polymarket prices a 46% chance SCOTUS accepts a prediction market case by year end. Most analyst projections place a cert decision between November and December 2026.