South Korean police have opened criminal cases against 26 users of Polymarket, the crypto-settled prediction market, over allegations of illegal gambling totaling roughly 17.6 billion won, or about $12.7 million. Of those 26, 18 have already been referred to prosecutors, according to data the national police agency submitted to a member of the ruling Democratic Party's office. The single largest individual betting amount under investigation reached approximately 5.7 billion won, or roughly $4.1 million, on its own.
Investigators didn't rely on a whistleblower or a platform disclosure to build the case. Police used open-source intelligence techniques to analyze publicly available blockchain transaction records, tracing on-chain activity back to individual users despite Polymarket's pseudonymous wallet structure. That approach reflects a broader shift in how gambling and financial-crime regulators are treating blockchain transparency: the same public ledger that crypto advocates often describe as a feature for auditability is, in cases like this one, exactly what lets law enforcement reconstruct a user's betting history without needing the platform's cooperation at all.
The legal basis for the crackdown is straightforward under Korean law. Betting on any platform other than Sports Toto — the state-run service operated by the Korea Sports Promotion Foundation, which caps individual bets at 100,000 won, or about $73 — is prohibited outright. Polymarket's structure, where users can wager far larger sums with no equivalent ceiling, put it squarely outside that framework the moment Korean residents began using it at scale. South Korea's communications regulator had already moved to block domestic access to the platform in August, citing concern that its winner-takes-all payout structure and event-based contracts could encourage speculative, addictive betting behavior similar to traditional gambling products.
Related: CFTC Ran Three Hidden Polymarket Insider-Trading Probes
The scale of this specific case is modest next to the broader scrutiny Polymarket has drawn elsewhere. In the US, the fight over how prediction markets should be regulated at all is still working through the courts, a parallel case pitting a CFTC rule against a New Jersey Supreme Court bid that remains unresolved, even as the platform keeps investing in infrastructure aimed at institutional users. South Korea's approach sidesteps that regulatory ambiguity entirely by treating the activity as ordinary illegal gambling under existing law, rather than waiting to classify prediction markets as a novel financial product first.
For the platform itself, the case adds to a growing list of jurisdictions treating Polymarket as a gambling product first and a financial or information market second, regardless of how the company positions itself. Polymarket has spent considerable engineering effort on infrastructure improvements aimed at institutional-grade users, but retail access in jurisdictions with strict gambling laws remains its most persistent legal exposure. With 18 of the 26 South Korean cases already referred to prosecutors, the next question is what penalties those users actually face — and whether prosecution of individual bettors, rather than action against the platform itself, becomes the template other Asian regulators follow.
FAQ
Why is Polymarket illegal for South Korean users specifically?
Korean law bans betting on any platform other than the state-run Sports Toto service, which caps individual wagers at about $73; Polymarket has no equivalent limit.
How did police identify anonymous Polymarket users?
Investigators used open-source intelligence techniques to analyze public blockchain transaction records, tracing on-chain betting activity back to individual users without needing cooperation from the platform.
What happens to the 18 users referred to prosecutors?
They now face potential criminal prosecution under South Korea's illegal gambling statutes; the police data doesn't specify penalties, which will be determined case by case.
Is Polymarket still accessible in South Korea?
No. The Korea Communications Standards Commission ordered domestic access blocked in August, citing concerns about the platform's winner-takes-all structure encouraging speculative gambling.
