Kalshi Has $6.7B in World Cup Volume — Bank of America Now Estimates $12-13B by the Final
Two weeks into the 2026 FIFA World Cup, Kalshi reports $6.7 billion in total World Cup trading volume, with a Bank of America analyst note estimating the platform will reach $12-13 billion by the July 19 final. Polymarket's soccer category crossed $2 billion in its first ten days alone, a 300% jump on pre-tournament levels with daily volume hitting $220 million. The numbers already eclipse the most optimistic pre-tournament projections.
Two weeks into the 2026 FIFA World Cup, the volume numbers coming out of the two major US prediction-market platforms are well past the optimistic end of pre-tournament estimates. Kalshi reports $6.7 billion in total World Cup trading volume, and a Bank of America analyst note puts the full-tournament figure at $12-13 billion by the July 19 final at MetLife Stadium in New Jersey. Polymarket's soccer category crossed $2 billion in its first ten days — a 300% jump compared to the equivalent period before kickoff — with daily volume in the category climbing from roughly $53 million to $220 million. Our pre-tournament piece projected record levels going in; the actual mid-tournament numbers are a different order of magnitude.
The two platforms are accumulating volume in structurally different ways, which tells you something about their user bases. Kalshi's open interest hit a record $1.16 billion during the tournament, meaning traders are holding positions over time — longer-horizon bets on who wins the group, who advances to the semifinals, who wins the title. Polymarket's overall open interest has remained relatively flat even as volume spiked, which implies heavy turnover: traders rotating in and out of positions on individual matches and short-dated contracts, closer to how a recreational bettor uses a sportsbook. Neither profile is obviously better — Kalshi's compounding OI suggests the emerging of larger directional traders, Polymarket's high-turnover pattern reflects the broader consumer base the World Cup attracts.
The podcast and media integration has accelerated alongside the volume. Polymarket teamed with Dear Media to launch 'What Are the Odds?', a weekly show with rotating celebrity hosts including Claudia and Jackie Oshry, Amanda Hirsch, and Heather McMahan, designed to make prediction-market odds accessible to a non-financial audience. Kalshi is partnering with the Men in Blazers Media Network for 'Night Cup' — a World Cup nightly recap with Roger Bennett — and a Kalshi-backed segment called 'Why Everyone Suddenly Believes' that tracks how market odds shift during the tournament. The media integrations are distribution plays: if prediction-market odds appear in mainstream sports coverage, the top of the acquisition funnel moves from finance-adjacent audiences to sports fans generally.
Two numbers worth keeping in mind as the knockout rounds approach. Spain remains the favorite across both platforms for the title market, the contract with the most aggregate volume in the tournament. Polymarket alone has $28 million or more concentrated on the Golden Boot market. Both figures will grow substantially as the field narrows and the stakes on individual outcomes increase. Bank of America's $12-13 billion Kalshi estimate was published before the round of 16 — the knockout-stage concentration effect, where every remaining match carries more weight, typically drives a second volume surge in the back half of any tournament. The question now is not whether this becomes the largest prediction-market event ever staged. It already is.
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Recent updates
Massachusetts Supreme Court Ruling on Kalshi Now Imminent — First State High Court Decision on Prediction Markets
The Massachusetts Supreme Judicial Court heard oral arguments on May 5 in the Kalshi prediction markets case and is expected to issue a decision within weeks. The SJC appeared skeptical of Kalshi's argument that CFTC regulation preempts state gambling law, and the court's ruling will be the first state supreme court decision on prediction markets anywhere in the country. Massachusetts AG Andrea Campbell secured a preliminary injunction blocking Kalshi's sports contracts in January 2026. The CFTC filed an amicus brief supporting Kalshi; a coalition of 38 state attorneys general filed an opposing brief supporting Massachusetts.
27 States Back California Tribes Suing Kalshi Over Sports Contracts Under Indian Gaming Law
Three California tribes — Blue Lake Rancheria, Chicken Ranch Rancheria of Me-Wuk Indians, and Picayune Rancheria of the Chukchansi Indians — are separately challenging Kalshi's sports event contracts in the Ninth Circuit under the Indian Gaming Regulatory Act, a federal law distinct from the Commodity Exchange Act preemption arguments at issue in Nevada, New Jersey, and Connecticut. The Ninth Circuit refused to consolidate the tribal case with the Nevada case. A Ninth Circuit panel appeared skeptical of Kalshi in July hearings, and 27 states plus the District of Columbia have filed amicus briefs supporting the tribes. The IGRA theory, if it succeeds, could block Kalshi from operating sports contracts in any state where tribal gaming compacts exist — a category that includes most US states.
SCOTUS Review of Prediction Markets Hits 64% on Polymarket — New Jersey Files Cert Petition September 3
The probability of Supreme Court review of prediction market sports contracts jumped from around 30% to 64% on Polymarket's own platform within hours of the Ninth Circuit's August 28 ruling — with $976,000 in trading volume flowing into the contract. New Jersey, the losing party in the Third Circuit's April ruling that went for Kalshi, is filing a certiorari petition on September 3. The Ninth Circuit's 3-0 ruling against Kalshi directly contradicts the Third Circuit's 2-1 ruling for Kalshi, creating the clearest possible circuit split trigger for SCOTUS to grant review.