World Cup Betting Pushes Prediction Markets into the Mainstream

Kalshi added 3mn users during the competition, while more than $1.2bn traded on its World Cup winner contract. Polymarket's equivalent market recorded $4.28bn. The activity capped a 12-month expansion that has propelled prediction markets to the forefront of global financial markets.

Football becomes the gateway

Prediction markets let users bet on whether something will happen, such as a candidate winning an election or a team winning a match. If a contract trades at $0.60, the market is roughly saying there is a 60% chance of that outcome. A correct bet pays $1, while an incorrect one pays nothing.

The World Cup, held from 11 Jun to 19 Jul, gave new users a simple entry point. Every goal, injury and red card could change prices in real time. Global interest also gave the largest contracts enough volume to act as information signals.

"The useful signal isn't the probability itself, it's the flow underneath it," Tim Sun, senior researcher at Hong Kong-based digital asset group HashKey, told Sandmark.

"That's the distinct difference between a sportsbook and a prediction market. While a sportsbook aggregates odds from professionals, a prediction market aggregates probabilities from everyone."

Polymarket and Kalshi both priced Spain at about 59% before the final against Argentina. Their separate order books indicated a broad consensus, although trading volume is not directly equivalent to sportsbook stakes because contracts can change hands repeatedly.

Kalshi also used the tournament as a customer-acquisition campaign through football partnerships, stadium advertising and celebrity-led marketing.

"Our volumes are where the news is at," Kalshi Chief Executive Tarek Mansour told CNBC.

Prices become information

The tournament showed why institutions are monitoring prediction markets as another source of information alongside bookmaker odds and exchange-based products.

Bookmakers set odds themselves, adjusting them to manage potential payouts and preserve a profit margin. Prediction markets are instead determined by participants buying and selling contracts directly, producing faster reactions as new information emerges.

A sharp move at high volumes can reveal new information. In a smaller market, the same move may instead reflect one trader, limited liquidity or unclear settlement terms.

During the World Cup, liquidity remained concentrated in major contracts. Tournament winner markets attracted billions of dollars, while narrower contracts had less depth. A precise probability can therefore overstate the quality of the underlying signal.

"A sports contract is intuitive, high-engagement, and settles on an outcome everyone understands," Sun said.

That familiarity may help platforms introduce users to contracts covering elections, economic data, entertainment and financial markets.

Sportsbooks feel the pressure

The World Cup also showed how prediction markets are competing with established betting operators for users.

H2 Gambling Capital estimated that prediction markets represented about 27% of legal US sports-betting volume during the tournament, up from 9% at the start of 2026.

Meanwhile, shares of traditional operators have struggled. DraftKings fell 16.9% between its 11 Jun closing price and 17 Jul, the final trading session before the final – bringing its year-to-date decline in 2026 to 27.6% as of 20 Jul. Flutter Entertainment, FanDuel's parent, declined 3.8% during the tournament and is down 50.5% year-to-date. Equity prices reflect multiple factors, but analysts have increasingly identified Kalshi and Polymarket as competitive risks.

The incumbents are responding. DraftKings launched its own exchange in June, while FanDuel expanded its prediction offering through regulated event-contract partners.

The next test is retention. Kalshi's volumes fell on days without matches. Mansour argued that other news would replace the tournament.