A measured surge in monthly turnover
Pew Research Center analysed The Block’s Kalshi and Polymarket series. The revised September 2026 release puts combined volume at $4.5bn in September 2025, $25.1bn in April 2026, $25.7bn in May, $47.7bn in June and $53.0bn in July. The chart below uses every reported rounded month from September 2025 through July 2026. An earlier May Pew article described April as about $24bn; the later underlying series is the consistent basis used here.
Sports drove much of the recent change
Pew reports more than $58bn of Kalshi sports trading over June and July 2026 combined, with Polymarket sports volume approaching $22bn over the same two months. That activity coincided with the men’s World Cup. A high-volume sports contract can trade many times before settlement, so trading turnover should not be treated as the amount won or lost by customers.
Kalshi, Polymarket and distinct audiences
The underlying collection includes Polymarket International and Polymarket US. Pew says Polymarket US grew from 4% of Polymarket volume in January 2026 to 39% in July. That is a platform mix measure, not proof that a UK resident can use either product. Market share depends on which venues an analyst includes.
What the figures leave out
Reported volume does not tell you how many people participated, whether a market was liquid at a useful price, what fees users paid, or how much of the flow was organic. Different data vendors and later revisions can change totals. For a UK access assessment, begin with our UK rules guide and provider terms rather than US trading headlines.
Combined Kalshi and Polymarket monthly volume
| Measure | USD billions |
|---|---|
| Sep 2025 | $4.5bn |
| Oct 2025 | $8.5bn |
| Nov 2025 | $10.1bn |
| Dec 2025 | $12.0bn |
| Jan 2026 | $17.5bn |
| Feb 2026 | $18.6bn |
| Mar 2026 | $24.3bn |
| Apr 2026 | $25.1bn |
| May 2026 | $25.7bn |
| Jun 2026 | $47.7bn |
| Jul 2026 | $53.0bn |
Reading note. Every month from September 2025 through July 2026. Rounded to one decimal from Pew’s revised series; turnover is not revenue.
Methodology.
Pew’s September release is the single basis for the chart, including its revised historical series; the May release is retained for context. Underlying platform data comes from The Block. No interpolated months, future values or UK extrapolations are shown.
Sources.
-
01
Trading volume on prediction markets has soared in recent months (opens in a new tab)
Independent analysisFunder: Pew Research Center; underlying trading series from The Block.
Historical snapshot through April 2026; later Pew analysis uses updated figures.
-
02
Prediction markets’ trading volume doubled between May and July, largely driven by sports (opens in a new tab)
Independent analysisFunder: Pew Research Center; underlying platform data from The Block.
Global Kalshi plus Polymarket volume, including Polymarket US; figures are trading turnover, not revenue or unique users.
Follow the original documents for definitions, scope and subsequent revisions. Browse the full source library ↗