The Wall Street Journal reported that in February, fraudsters linked stolen debit cards to Polymarket US accounts, attempting to transfer at least $10 million through betting and withdrawals. At one point, the platform's payment processor rejected over 80% of its processed deposits due to fraud, a figure significantly higher than the industry average of approximately 1%. According to sources, in response to employee concerns, CEO Shayne Coplan stated he would continue to expand the business and pay fines if regulators discovered the issue. Polymarket stated that the company has established processes to detect and respond to suspicious activities and is committed to cooperating with regulators and law enforcement.