Polymarket Faces $10 Million Fraud Scheme Amid Weakened Security Measures

Polymarket, a popular prediction market platform, has been embroiled in a significant fraud scheme that exploited its weakened anti-money-laundering controls, leading to attempted fraudulent transactions totaling at least $10 million. This incident, which occurred in February 2026, involved fraudsters using stolen debit cards to create numerous accounts and place bets on the platform.

According to reports from The Wall Street Journal and Crypto Briefing, the payment processor Checkout.com flagged over 80% of these transactions as suspicious, a stark contrast to the industry norm of approximately 1%. Internal compliance teams at Polymarket had raised concerns about escalating fraud risks, but CEO Shayne Coplan reportedly prioritized growth over security, suggesting that the company could address potential fines later.

One critical decision made by leadership was the removal of a “same-source” withdrawal requirement, a standard safeguard designed to prevent money laundering by ensuring that funds could only be withdrawn to the same account from which they were deposited. This decision directly contributed to the vulnerabilities that the fraudsters exploited.

In response to the fallout, Polymarket has since implemented stricter controls, including limits on the number of debit cards linked to a single account and engaging a fraud detection firm, Riskified, to enhance its security measures. Several senior compliance executives departed during this period, and the company has initiated an internal review to ensure compliance with applicable regulations.

As Polymarket prepares for potential growth initiatives, including a possible IPO, the incident highlights the unique compliance challenges faced by prediction markets, particularly those accepting fiat deposits.