Prediction markets’ trading volume doubled between May and July, largely driven by sports

San Diego Padres player Fernando Tatís Jr. throws a baseball in front of a Kalshi ad on Sept. 4, 2026, at Petco Park in San Diego. (Meg McLaughlin/The San Diego Union-Tribune via Getty Images) The combined monthly global trading volume on Kalshi and Polymarket – the two leading prediction markets – more than doubled in the span of two months. It rose from $26 billion in May to $53 billion in July, according to a Pew Research Center analysis of data from The Block, a digital assets media and information firm. Trading volume on prediction markets doubled between May and July Combined monthly global trading volume on Kalshi and Polymarket, in U.S. dollars Note: Polymarket includes Polymarket US. Data is shown through July 2026. Source: Pew Research Center analysis of data from The Block, accessed September 2026. PEW RESEARCH CENTER Trading volume on prediction markets doubled between May and July Combined monthly global trading volume on Kalshi and Polymarket, in U.S. dollars DateMonthly volume (in billions)dateMonthly volumeJuly 20240.82024-07-01$810,231,927.05August 20240.92024-08-01$889,690,193.93September 20240.92024-09-01$886,548,758.99October 20244.52024-10-01$4,546,131,855.57November 20244.72024-11-01$4,736,833,877.29December 20243.52024-12-01$3,472,097,795.44January 20252.82025-01-01$2,825,966,293.83February 20251.72025-02-01$1,717,326,486.88March 20251.72025-03-01$1,740,704,351.76April 20251.82025-04-01$1,773,182,461.50May 20251.92025-05-01$1,937,092,835.73June 20252.12025-06-01$2,113,137,094.95July 20252.02025-07-01$2,015,772,965.99August 20252.02025-08-01$1,977,744,667.34September 20254.52025-09-01$4,509,324,555.78October 20258.52025-10-01$8,501,556,797.53November 202510.12025-11-01$10,140,548,557.42December 202512.02025-12-01$11,982,489,242.53January 202617.52026-01-01$17,494,802,139.39February 202618.62026-02-01$18,642,066,732.01March 202624.32026-03-01$24,269,021,557.79April 202625.12026-04-01$25,077,603,914.82May 202625.72026-05-01$25,660,233,390.29June 202647.72026-06-01$47,745,711,033.65July 202653.02026-07-01$52,993,451,895.61 Note: Polymarket includes Polymarket US. Data is shown through July 2026. Source: Pew Research Center analysis of data from The Block, accessed September 2026. PEW RESEARCH CENTER This increase was mostly due to a large uptick in sports trading. Sports is now the most traded topic on both platforms by a large margin. Previously, the Center has found that sports traders tend to place more trades than those who focus on other topics. In June and July, coinciding with the FIFA World Cup, sports trading topped $58 billion on Kalshi and neared $22 billion on Polymarket. For comparison, Americans wagered around $40 billion on legal sportsbooks in the first quarter of 2026 – about on par with the combined prediction market trading volume on sports over the same period of time. Some regulators have argued that these sports contracts amount to offering sports betting nationwide, in violation of state and local gambling regulations. About this research This Pew Research Center analysis looks at trading volume on the two major prediction markets, Kalshi and Polymarket, from July 2024 through July 2026. Why did we do this? Pew Research Center does research to help the public, media and decision-makers understand important topics. This research builds on our recent work on gambling and the broader prediction economy – including public attitudes toward sports betting and views of the morality of gambling in countries around the world. Learn more about Pew Research Center. How did we do this? Data on Kalshi, Polymarket International and Polymarket US comes from The Block, a digital assets media and information firm. Throughout this analysis, Polymarket refers to both Polymarket International and Polymarket US unless otherwise specified. There are different ways to measure the volume of trading on prediction markets. In this analysis, trading volume refers to notional taker volume in U.S. dollars, which is the number of contracts traded by takers. Each contract is counted at its $1 notional value, or the value of the contract if it is correct, rather than the price at the time of the trade. For this analysis, we used categories reported by The Block to create topic areas that are comparable across the two platforms. For example, what we report as “politics” includes the categories “politics” or “elections” on Kalshi and “politics,” “geopolitics” or “elections” on Polymarket. For Kalshi, The Block reports categories as they come from the platform, except for combos, which are tagged as a separate category that The Block maps onto substantive categories where possible. Due to changes in the availability of category data for combos, we limited our analysis by ending in July 2026. For Polymarket International, The Block relies on topical tags provided by the platform and uses the first tag listed to create categories. For Polymarket US, The Block reports categories as they come from the platform. Categories reported by The Block are mutually exclusive. What are prediction markets? To trade on the outcome of events, prediction market users buy and sell event contracts with binary outcomes valued between $0 and $1. The price of the contract is meant to represent the likelihood of the outcome happening. For example, a “yes” contract valued at 40 cents is meant to represent a 40% chance that an outcome will happen. Once a market is resolved, a winning contract is worth $1. In other words, a user pays 40 cents to buy the contract and receives $1 if the outcome happens. While our analysis ends in July due to category data limitations, the spike doesn’t appear to simply be a temporary World Cup boost. Despite both platforms seeing a slight decline in trading volume in August, they still closed out at a combined $47 billion. Early data for September suggests trading volume is ticking back up, alongside the start of football season. Sports is the top source of trading volume on both Kalshi and Polymarket Monthly global trading volume on Kalshi and Polymarket, in U.S. dollars Note: Polymarket includes Polymarket US. Data is shown through July 2026. Source: Pew Research Center analysis of data from The Block, accessed September 2026. PEW RESEARCH CENTER Sports is the top source of trading volume on both Kalshi and Polymarket Monthly global trading volume on Kalshi and Polymarket, in U.S. dollars Kalshi monthly volume (in millions)Polymarket monthly volume (in millions)DateSportsPoliticsCryptocurrencyOtherSportsPoliticsCryptocurrencyOtherJuly 20240.00.91.826.219.3733.812.615.5August 20240.00.81.821.658.6742.514.150.3September 20240.01.01.918.5127.5629.823.584.3October 20240.0263.53.912.71074.72960.3154.176.9November 20240.01127.768.674.41053.12059.5157.9195.6December 20240.190.565.969.61904.6934.8187.4219.2January 20257.782.331.353.61552.1537.5165.8395.6February 202537.542.536.969.6953.8294.1163.4119.5March 2025405.930.931.053.4439.5317.6129.4333.1April 2025296.839.031.493.2339.2547.7155.4270.5May 2025509.323.929.7101.5302.1625.6175.6169.5June 2025619.837.937.486.7290.6657.2256.6126.9July 2025541.733.961.2103.6326.0221.4290.6437.5August 2025657.627.297.592.1384.0289.8319.3110.2September 20252561.840.599.1162.2676.7528.9288.1151.9October 20253953.7133.1125.0186.11427.61281.5799.6595.0November 20255256.8234.7128.9189.51749.5855.71028.0697.3December 20255995.182.6184.7321.72071.31214.31436.8676.1January 20268519.7259.9340.2434.53382.82098.51819.5639.7February 20268522.6297.8793.3822.73219.41964.02399.4622.9March 20269962.9194.61211.21626.45007.22547.32923.5796.0April 202611519.2204.91358.11725.64729.02488.71873.21178.9May 202612981.4213.11882.21737.15037.41435.01333.21040.9June 202626610.4261.24012.82118.211381.01263.91649.3448.8July 202631395.7169.26101.12437.110618.5726.81154.1391.0 Note: Polymarket includes Polymarket US. Data is shown through July 2026. Source: Pew Research Center analysis of data from The Block, accessed September 2026. PEW RESEARCH CENTER How are trading patterns different on Kalshi and Polymarket? Sports is now the largest category on both Kalshi and Polymarket, but there are some differences in trading patterns between the two platforms. Trading on Kalshi has accelerated more rapidly. As recently as March of this year, Kalshi and Polymarket each had around 50% of prediction markets’ total trading volume. Since then, trading has increased dramatically on Kalshi and more modestly on Polymarket. Cryptocurrency has grown as a share of Kalshi’s trading volume. Cryptocurrency trading on Kalshi has been growing steadily in recent months and totaled $6 billion in July. That makes it the second-most traded topic on Kalshi, although it is dwarfed by sports trading. Trading on politics is uncommon relative to other topics, but more prevalent on Polymarket. Monthly trading volume related to politics has averaged around $2 billion on Polymarket since the start of 2026. On Kalshi, it has consistently remained under $300 million. Politics was the largest category on both platforms during the 2024 U.S. presidential election. Related: More than half of states restrict betting on elections Polymarket US takes a more prominent role. Polymarket, which has faced legal trouble for allowing Americans to place trades on its unregulated international platform, introduced the CFTC-regulated Polymarket US in late 2025. Since then, Polymarket US has grown steadily: Its share of Polymarket’s total trading volume rose from 4% in January to 39% in July. Kaitlyn Radde is a computational social science assistant at Pew Research Center.