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

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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)
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 volume
July 20240.82024-07-01$810,231,927.05
August 20240.92024-08-01$889,690,193.93
September 20240.92024-09-01$886,548,758.99
October 20244.52024-10-01$4,546,131,855.57
November 20244.72024-11-01$4,736,833,877.29
December 20243.52024-12-01$3,472,097,795.44
January 20252.82025-01-01$2,825,966,293.83
February 20251.72025-02-01$1,717,326,486.88
March 20251.72025-03-01$1,740,704,351.76
April 20251.82025-04-01$1,773,182,461.50
May 20251.92025-05-01$1,937,092,835.73
June 20252.12025-06-01$2,113,137,094.95
July 20252.02025-07-01$2,015,772,965.99
August 20252.02025-08-01$1,977,744,667.34
September 20254.52025-09-01$4,509,324,555.78
October 20258.52025-10-01$8,501,556,797.53
November 202510.12025-11-01$10,140,548,557.42
December 202512.02025-12-01$11,982,489,242.53
January 202617.52026-01-01$17,494,802,139.39
February 202618.62026-02-01$18,642,066,732.01
March 202624.32026-03-01$24,269,021,557.79
April 202625.12026-04-01$25,077,603,914.82
May 202625.72026-05-01$25,660,233,390.29
June 202647.72026-06-01$47,745,711,033.65
July 202653.02026-07-01$52,993,451,895.61
Download data as .csv
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
Chart
Chart
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)
DateSportsPoliticsCryptocurrencyOtherSportsPoliticsCryptocurrencyOther
July 20240.00.91.826.219.3733.812.615.5
August 20240.00.81.821.658.6742.514.150.3
September 20240.01.01.918.5127.5629.823.584.3
October 20240.0263.53.912.71074.72960.3154.176.9
November 20240.01127.768.674.41053.12059.5157.9195.6
December 20240.190.565.969.61904.6934.8187.4219.2
January 20257.782.331.353.61552.1537.5165.8395.6
February 202537.542.536.969.6953.8294.1163.4119.5
March 2025405.930.931.053.4439.5317.6129.4333.1
April 2025296.839.031.493.2339.2547.7155.4270.5
May 2025509.323.929.7101.5302.1625.6175.6169.5
June 2025619.837.937.486.7290.6657.2256.6126.9
July 2025541.733.961.2103.6326.0221.4290.6437.5
August 2025657.627.297.592.1384.0289.8319.3110.2
September 20252561.840.599.1162.2676.7528.9288.1151.9
October 20253953.7133.1125.0186.11427.61281.5799.6595.0
November 20255256.8234.7128.9189.51749.5855.71028.0697.3
December 20255995.182.6184.7321.72071.31214.31436.8676.1
January 20268519.7259.9340.2434.53382.82098.51819.5639.7
February 20268522.6297.8793.3822.73219.41964.02399.4622.9
March 20269962.9194.61211.21626.45007.22547.32923.5796.0
April 202611519.2204.91358.11725.64729.02488.71873.21178.9
May 202612981.4213.11882.21737.15037.41435.01333.21040.9
June 202626610.4261.24012.82118.211381.01263.91649.3448.8
July 202631395.7169.26101.12437.110618.5726.81154.1391.0
Download data as .csv
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.   

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Kaitlyn Radde is a computational social science assistant at Pew Research Center.