Study: Americans Traded Up to $34B on Banned Offshore Prediction Markets

• The Coalition for Prediction Markets (CPM) estimates that U.S. residents have traded up to $34 billion on illegal, unregulated offshore platforms
• Group estimates that figure could quadruple by 2030
• Polymarket accounts for the bulk of that volume

The Coalition for Prediction Markets (CPM), a trade association comprised of regulated US prediction market operators, released a study today (June 11) indicating that illegal, offshore yes/no exchanges processed as much as $34 billion in event contract volume from US users.

Conducted in conjunction with Rutgers University professor Harry Crane, an expert in sports betting and statistics, the study reveals that from April 2025 through May 2026, bettors and traders in the US moved $11 billion to $34 billion through unlicensed prediction markets with nearly two-thirds of that volume attributable to Polymarket.

The offshore and unregulated prediction market industry could grow to $133 billion by 2030 — surpassing the combined size of America’s video game and recorded music industries,” said CPM President Sean Patrick Maloney.  “The choice is not whether these markets exist, but whether they operate here in the United States under transparent federal oversight or migrate to opaque offshore platforms where unseemly markets on death and war proliferate.”

Polymarket, which lays claim to being the world’s largest yes/no exchange by volume, launched its iOS app in May so it’s possible that more of that operator’s US-driven turnover will enter the “legal” column over time.

Offshore Prediction Market Volume Declining

While the CPM warns that offshore prediction market volume could roughly quadruple from the high end of its April 2025-May 2026 estimate, the study also acknowledges that regulated markets are growing faster than unlicensed counterparts.

Narrowing the gap is important for the industry because offshore sports wagering still draws a crowd. In 2025, regulated sportsbooks in this country generated a combined handle of $168 billion, but some estimates indicate the offshore figure was $300 billion to $330 billion.

“Still, roughly one in six dollars tied to U.S. prediction market activity is currently flowing through offshore platforms outside U.S. regulatory oversight. If current trends continue, that figure is projected to reach $133 billion annually by 2030,” observes the CPM study.

Why Some Prediction Market Traders Go Offshore

The CPM study doesn’t get into traders’ motivations for embracing offshore prediction markets, but reasons likely include access to crypto-native, decentralized platforms, of which Polymarket is one. Other motivations include reduced trading friction, lower margin requirements and expanded access to leverage as well as more robust menus of trading options.

In addition to Polymarket, other big names in offshore prediction markets include Limitless, Myriad, plus Opinion and Predict.

Among the regulated US yes/no exchanges, Kalshi is far away the leader in terms of market share. Kalshi and Crypto.com are founding members of the CPM and are joined in the organization by Coinbase Global (NASDAQ: COIN), Robinhood Markets (NASDAQ: HOOD), and Underdog.