Trading volume on Polymarket's United States exchange more than tripled between June and October, rising approximately 266% even as the prediction market platform faced intensifying scrutiny from state and federal regulators.

Monthly volume on the US exchange climbed to $14.77 billion in October from $4.04 billion in June, according to data from analytics platform TickerTracker, which counts trades at the contracts' full payout value. Prediction markets let traders buy and sell contracts tied to the outcomes of real-world events, with prices reflecting the market's collective assessment of each outcome's likelihood.

Polymarket told CNBC on Tuesday that its annualized revenue had topped $1.8 billion, up from more than $1 billion in June.

Combo contracts, which bundle multiple predictions into a single wager, represented the largest share of October's activity, generating $8.6 billion, or 58.2% of total volume. Sports contracts followed at $4.57 billion, or 31%.

The platform's US arm has expanded rapidly since the company widened access in May, even as states challenge whether federally regulated prediction markets can offer sports contracts without state gambling licenses. Polymarket began admitting US traders to the separate exchange in late 2025, three years after a settlement with the Commodity Futures Trading Commission (CFTC) led it to block US trading on its international platform.

Sports trading also received a boost from the FIFA World Cup, which ran from June 11 to July 19. Soccer contracts generated $1.81 billion in trading volume in June, up from $85.4 million in May, according to TickerTracker.

Political markets likewise saw increased activity surrounding the US midterm elections. Election-related contracts produced $108.2 million in trading volume on Polymarket's US exchange during the first 10 days of November, compared with $16.6 million throughout September. Even so, political markets accounted for just 2.2% of the platform's November trading volume.

Meanwhile, Polymarket is pursuing a $1 billion funding round at a reported $21 billion post-money valuation. Investment firm 1789 Capital, where Donald Trump Jr. is a partner, is reportedly leading the round with an expected contribution of about $300 million.

Polymarket faces mounting legal challenges

Despite the strong figures, Polymarket continues to face regulatory scrutiny on several fronts. The CFTC was reportedly investigating the company earlier this year, and in June US Senators John Curtis and Adam Schiff separately called on the regulator to examine allegations that Polymarket paid social media influencers to promote fabricated trades.

Responding to the allegations, the company told Cointelegraph that it was “conducting a comprehensive audit of active promotional content to ensure it complies with our standards, as well as applicable regulatory and legal disclosure requirements.”

Polymarket is also among several prediction market operators facing legal challenges from US states. In September, New York Attorney General Letitia James sued the company, alleging that its sports-related event contracts violated state gambling laws. The lawsuit forms part of a broader wave of state actions against prediction market platforms, including Kalshi, over whether their contracts fall under federal commodities regulation or state gambling laws. The stakes of that dispute extend across the industry, as sports-related contracts have made up a substantial share of trading activity on platforms like Polymarket.

The CFTC has defended its authority to regulate prediction markets, pursuing legal action involving 10 states over efforts to enforce state gambling laws against the platforms. The jurisdictional dispute could ultimately reach the US Supreme Court. In September, New Jersey officials petitioned the court to hear their case against Kalshi, seeking a ruling that could clarify which authorities hold jurisdiction over sports-related prediction markets. Whether the court agrees to take up the case, and how the New York lawsuit proceeds, will be key developments to watch as Polymarket's US expansion continues.