South Korea's Gangwon Provincial Police Agency booked 26 Polymarket users in a gambling investigation involving approximately ₩17.6 billion, or about $12.7 million, in cumulative bets tied to political, economic and social outcomes. Eighteen suspects were referred to prosecutors. The case was disclosed on September 17 through data from Democratic Party lawmaker Yoon Geon-young's office. Police are assessing the activity under Article 246 of South Korea's Criminal Act, while users argue that Polymarket is closer to a crypto-based derivatives venue than a gambling platform. Investigators reportedly identified participants by tracing public blockchain transactions because Polymarket did not hold Korean users' real-name records. Domestic access to the platform was reportedly blocked in August 2026. The referrals do not amount to charges or convictions, and South Korean courts have not resolved whether prediction-market contracts settled in USDC constitute gambling or derivatives investments.