Prediction-Market Bias Gives U.S. and Mexico Teams a Premium on Kalshi and Polymarket
Kalshi and Polymarket are prediction markets where contract prices reflect the probability of events. Research focused on the 2026 World Cup found that the composition of each platform's user base influences capital flows. When traders are constrained by nationality and access rules, market prices may reflect systematic national preferences rather than a global consensus.
The latest study compared U.S.-only Kalshi with globally accessible Polymarket. It found that Kalshi users allocated five to six times more money than justified to bets on the U.S. and Mexico teams, while the relevant contracts persistently traded at premiums of up to 40%. The findings indicate that cross-platform arbitrage is insufficient to eliminate the bias.
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The history behind this eventKalshi Outpaces Polymarket as World Cup Cements Prediction-Market Duopoly
Prediction markets let traders wager on real-world outcomes, making the 2026 FIFA World Cup a major test of the sector’s ability to attract mainstream users. Kalshi and Polymarket now account for more than 95% of the market, cementing a duopoly in which scale, consumer reach and marketing spending increasingly determine which platform converts attention into trading activity.
After the tournament concluded in July 2026, Kalshi reported $54.338 billion in total platform trading volume, 2.6 times Polymarket’s tally. Kalshi also led in app downloads and aggregate trading value, helped by heavy advertising spending. Polymarket continued to draw more website visits, but that traffic did not translate into a volume lead, leaving Kalshi ahead on the industry’s most closely watched commercial measures.
World Cup Fuels Prediction-Market Boom as Kalshi, Polymarket Volume Jumps 75%
Prediction markets allow users to trade contracts tied to the outcomes of sporting, political and other events, with prices reflecting the market-implied probability of each result. Betting demand generated by the 2026 FIFA World Cup rapidly expanded Kalshi and Polymarket, bringing greater scrutiny to their liquidity, compliance and regulatory disputes across U.S. states.
Kalshi and Polymarket recorded a combined $44.8 billion in trading volume in June 2026, up 75% from May. Kalshi's monthly volume surged 87.4% to a platform record. Polymarket also returned to growth, supported by World Cup enthusiasm and U.S. market demand, though both companies continued to face regulatory challenges from several U.S. state governments.
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