Polymarket faces fresh scrutiny following a September 19 report revealing that bad actors utilized stolen debit cards on its U.S. platform in February to launch attempted illicit wagers and withdrawals totaling at least $10 million.
According to the report, criminals linked stolen cards to thousands of Polymarket US accounts, funded them, and subsequently attempted to cycle the money through trading activity before withdrawing the funds to accounts or cards under their control.
During the peak of the February attacks, payment processor Checkout.com flagged and rejected over 80% of the deposits it processed for Polymarket as fraudulent, the Wall Street Journal reported. This compares starkly to typical industry fraud levels of roughly 1%. Checkout.com has not independently verified the 80% figure in any public statement reviewed for this coverage. While Checkout.com equips merchants with authentication tools, transaction filtering, and fraud-scoring capabilities, its service terms stipulate that merchants ultimately retain responsibility for accepting or canceling transactions.
Current and former staff members informed the newspaper that compliance personnel raised urgent concerns regarding the surge in illicit activity directly to Polymarket CEO Shayne Coplan. According to sources cited by the publication, Coplan’s response surprised certain employees by seemingly prioritizing rapid growth above all else.
Following the incident, Polymarket implemented stricter card controls, which the platform stated brought fraud rates back down to standard industry norms. Polymarket US currently operates via QCX—a designated contract market overseen by the Commodity Futures Trading Commission (CFTC) subject to federal derivatives regulations. In addition, the company recently appointed Warren Jenson as its Chief Financial Officer while simultaneously bolstering its staffing across compliance, risk management, and internal investigations.
Frequently Asked Questions
What is Polymarket?
Polymarket is a prediction and betting platform that operates a U.S. presence through QCX, which is a CFTC-designated contract market subject to federal derivatives oversight.
How much fraudulent activity did Polymarket face?
Fraudsters attempted at least $10 million in illicit withdrawals and wagers using stolen debit cards on the U.S. platform in February.
What role did Checkout.com play in the incident?
Checkout.com served as the payment processor and reportedly rejected more than 80% of Polymarket US deposits as fraudulent during the peak of the attack in February.
How did Polymarket respond to the fraud surge?
The platform introduced stronger card controls that it says brought fraud rates back down to industry norms, hired Warren Jenson as CFO, and expanded its compliance, risk management, and investigations staff.