Eleven days into the 2026 FIFA World Cup, prediction market platforms Kalshi and Polymarket have processed more than $5.4 billion in wagers — already exceeding the combined betting volume of March Madness and this season’s Champions League — in a boom that has produced multimillion-dollar windfalls, intensified scrutiny over potential insider trading, and positioned this tournament as the clearest test yet of whether prediction markets can rival traditional sportsbooks at scale.
Argentina and Spain are riding high after dominant World Cup performances, inching them closer to the tournament’s knockout stage. But prediction market firms like Kalshi and Polymarket are celebrating in equal measure. Just 11 days into the tournament, and with a month still remaining, this upstart sector of the betting industry, which allows users to bet on sports and a wide variety of other real-world events, has already notched billions of dollars in wagers.
That figure has already exceeded other marquee sports events, including March Madness, which saw the firm bring in $2.51 billion, and this season’s Champions League, where bets totalled $685 million.
The scale of this comparison is worth sitting with: a single World Cup, not yet at its midpoint, has already out-drawn the entirety of America’s most prediction-market-friendly annual basketball tournament, combined with the entire continental club football season’s flagship competition. And the World Cup still has a month to go.
The Platform-by-Platform Numbers
To assess the extent of the impact, Fortune collected data from leading prediction markets as of Thursday. Kalshi showed the largest increase: the platform reports that World Cup trading volume has reached $2.9 billion, including combination bets, and continues to rise.
Kalshi has already surpassed $7.49 billion in notional volume for the week of June 15, surpassing its prior record of $6.38B with Sunday’s session still open. The partial total runs 17.5% above the previous record through just six closed days, putting Kalshi on track for its first $8B-plus week — a likely $8.5B to $8.9B [total].
Polymarket, a major rival to Kalshi in the space, has reported similarly strong activity. According to a person familiar with the company, Polymarket’s World Cup wagers have generated $2.5 billion in cumulative trading volume since launching last July, making it one of the largest single markets in the platform’s history. Over the same period, soccer-related trading on its global decentralized finance platform has exceeded $5 billion.
The Million-Dollar Trades
Since the start of the World Cup, both outcomes have already played out. In the Portugal–Congo match, a Polymarket user with the handle “BreakTheBank” wagered just under $300,000 that Portugal would not win and ultimately booked a profit of nearly $1 million when the match ended. In another instance, a newly created wallet placed a $4 million bet on the same platform that Spain would not beat Cabo Verde and walked away with roughly $9 million, prompting public questions about whether the trade reflected good luck or access to nonpublic information.
More than $5 billion has been traded on the World Cup across Polymarket’s international exchange and US-regulated Kalshi Inc. in 2026, according to a Bloomberg News analysis of Dune Analytics data and company records. The boom has produced multimillion-dollar winners and some painful losses, including a bet-gone-wrong on Belgium to beat Egypt that cost one Polymarket user nearly $9 million.
The specific case of a newly created wallet placing a $4 million wager that produced a $9 million payout — flagged explicitly by Fortune as having “intensified concerns about insider activity on prediction platforms” — touches on one of the most consequential structural risks facing this entire emerging sector. These kinds of trades have intensified concerns about insider activity on prediction platforms. Some countries have moved to ban or block certain markets entirely, and in the United States, the rapid growth of event contracts has sparked an ongoing fight between federal regulators and state authorities over [jurisdiction].
How Big Could This Get?
Per the BBC, Macquarie analyst Chad Beynon projects global wagers could top $50 billion (roughly $500 million per match on average), up from the $35 billion figure from the 2022 tournament in Qatar.
The jump tracks the expanded format: 48 teams playing 104 matches across the US, Canada, and Mexico makes for 40 more games compared to four years ago. There is also a difference in where the money can flow. This is the first modern World Cup to land with most of the U.S. able to bet legally – about 65% of the population, up from roughly 40% in 2022 – and the first in which regulated prediction markets are taking action alongside sportsbooks.
The combination of a structurally larger tournament (48 teams rather than 32, generating 104 matches rather than 64) and a significantly expanded legal betting footprint within the United States explains much of why this tournament’s prediction-market figures are dwarfing prior benchmarks, even relative to the genuinely substantial $35 billion wagered globally during the 2022 Qatar World Cup.
The Regulatory Fight Underneath the Boom
The CFTC proposed a rule on June 10 to define sports event contracts as “gaming” while permitting most of them, even as several states pursue Kalshi for what they call illegal sports betting. Whether the World Cup’s contract volume cements prediction markets as a fixture or hands regulators ammunition is now an open question.
This regulatory uncertainty — a federal agency moving to formally classify and largely permit these contracts, even as individual states pursue separate legal action against the same platforms for what they characterise as unlicensed sports betting — means the World Cup’s record-shattering volume is unfolding inside a genuinely unresolved legal framework. The outcome of that jurisdictional dispute, likely to be substantially informed by how this tournament’s volume and visibility ultimately play out, could determine whether prediction markets become a permanently established feature of American sports culture or face significant new constraints in the aftermath of this summer’s boom.
Sports contracts now account for a significant portion of monthly trading volumes, with Polymarket and Kalshi reporting combined figures rising from less than $5 billion in September 2025 to $24 billion in April 2026.
That trajectory — from under $5 billion to $24 billion in combined monthly volume across just eight months, even before the World Cup’s own dramatic contribution — suggests this growth pattern was already well underway before the tournament began, with the World Cup serving as an accelerant rather than the sole cause of an already-rapidly-expanding sector.
LoudFact.com is an independent global news and explainer platform. This report is based on reporting from Fortune, Bloomberg, DeFi Rate, PlayUSA, Bitcoin.com, World Casino Directory, SportsbookReview, and Polymarket’s own market data as of June 22, 2026.
