Polymarket’s World Cup Winner market reached $3.9 billion in trading volume by July 5, making it the platform’s largest single contract by volume. The company also said annualized revenue crossed $1 billion during the tournament surge.
TechTimes reported that the total has built since the market launched in July 2025. As the tournament entered the Round of 16, France was trading at 35 cents a share, implying a 35% chance, while Argentina traded at 17%.
Prediction markets are peer-to-peer exchanges in which users buy shares priced in cents that pay out $1 if the outcome resolves correctly. Polymarket runs on Polygon, settles in USDC and uses an off-chain central limit order book before on-chain settlement through smart contracts.
Kalshi operates differently, as a CFTC-registered exchange that holds user funds in U.S. dollars. TechTimes said it offers ACH and bank-wire deposits, pays 3.75% to 4% APY on balances and caps most market positions at $25,000 per trader.
The World Cup surge has lifted the wider sector, too. CNBC reported that Kalshi did more than $31 billion in notional volume in June, up more than 70% from May’s $17.9 billion, while Polymarket’s international exchange topped $10.8 billion and set a new monthly record.
Polymarket’s U.S. platform did more than $3.5 billion in June, up from $1.77 billion in May. On tournament outcome markets, more than $64 million had been traded on Kalshi and $122 million on Polymarket, with open interest above $1 billion on Kalshi and just under $400 million on Polymarket.
The frenzy was visible in individual matches. TechTimes said the Norway vs Senegal group-stage game drew more than $32 million on Polymarket alone, and one trader staked more than $1.1 million on Croatia vs Ghana in the Round of 32.
Investor appetite has tracked the volume spike. TechTimes said Polymarket was valued at $15 billion after a March funding round, Kalshi at $22 billion after raising $1 billion in May, and the New York Stock Exchange invested $600 million in Polymarket.
According to the Congressional Research Service, prediction markets are exchange platforms that sell binary event contracts and use continuous buying and selling to set prices. It said sports have become the dominant category, with about 87% of Kalshi’s $39.7 billion traded in the past year and 38% of Polymarket’s $36.2 billion tied to sports.
That growth has intensified a legal fight over whether sports event contracts should be treated as derivatives or gambling. TechTimes said the platforms’ U.S. strategy depends on a Commodity Exchange Act preemption argument, while the CFTC under Chairman Michael Selig has filed nine lawsuits against states asserting exclusive federal jurisdiction.
States have answered with injunctions and new taxes. TechTimes reported that at least 18 states have taken some form of legal action and at least three have won court orders that can halt access entirely, including Michigan’s temporary restraining order on June 30 and Nevada’s denied emergency stay.
Polymarket separately sued New Mexico’s attorney general last week to block an imminent enforcement action, and Minnesota’s new law would make operating or helping to operate a prediction market a state felony when it takes effect on Aug. 1. North Carolina has passed a 6% revenue tax and New Jersey is advancing a 9% surtax.
Judge Katherine Menendez questioned whether sports event contracts are meaningfully different from traditional sports betting and called the preemption case an uphill battle. Jeffrey Alberts said the preemption question is real but that the Commodity Exchange Act was not designed to address addiction and public-safety concerns.
Politico reported that the Commodity Futures Trading Commission was conducting an extensive investigation into Polymarket. Separately, TechTimes reported that a June 25 frontend hack drained $3.1 million from 11 confirmed wallets, and that Polymarket was investigating a five-month paid-creator campaign that accumulated more than 140 million views.
The CFTC’s proposed rulemaking published in June has a comment period that closes on July 27.
