Polymarket’s $10M Fraud Attempt Puts Rapid U.S. Growth Under Scrutiny

Polymarket’s rapidly expanding U.S. prediction-market business faced a major test in February after fraudsters attempted to move at least $10 million using stolen debit cards, according to The Wall Street Journal.

The attackers allegedly linked stolen cards to Polymarket US accounts, placed wagers, and then routed proceeds toward clean cards or accounts they controlled. The incident exposed pressure on the safeguards supporting Polymarket’s expansion in the United States.

WSJ: Polymarket CEO Reportedly Told Staff to Keep Growing and Pay a Fine if Regulators Found Out Amid $10M Stolen-Card Fraud Attempt The Wall Street Journal reported that fraudsters linked stolen debit cards to Polymarket US accounts in February, attempting to move at least $10… pic.twitter.com/hbBJEJF3Fi — Wu Blockchain (@WuBlockchain) September 20, 2026

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The scale of the activity strained Polymarket’s payment controls. Checkout.com reportedly rejected more than 80% of the deposits it processed as fraudulent at one point, compared with an industry rate of roughly 1% cited by the Journal.

Fraud Attempt Tests Polymarket’s U.S. Growth Controls

Current and former employees told the Journal that compliance staff escalated the surge to Chief Executive Shayne Coplan. According to those sources, Coplan urged the company to continue expanding and suggested paying a fine if regulators later intervened.

Polymarket has not publicly confirmed that account. The episode occurred as the company was building a regulated U.S. presence. CFTC records show that QCX LLC began operating under the Polymarket US name after receiving designated contract market status on July 9, 2025.

That status places the platform within a federal derivatives framework as its business continues to expand. Polymarket also has a prior enforcement history with the regulator. In 2022, the CFTC ordered its operator to pay $1.4 million for offering event-based binary options without the required registration.

According to the Journal, fraud levels remained elevated for months before moving closer to industry norms by May. Polymarket subsequently reduced the number of debit cards users could connect and hired the fraud-prevention firm Riskified.

Tighter Safeguards Follow Elevated Fraud Levels

The Information separately reported that Visa pushed Checkout.com to strengthen its controls after chargebacks and failed transactions increased. Riskified has also warned that prediction markets face risks including account takeovers, rapid-withdrawal schemes, and card-number attacks.

The Journal later reported another security incident affecting nearly 500 users, adding pressure on Polymarket’s risk systems. The newspaper also reported that the CFTC is investigating the company.

Employees were instructed to preserve records related to the February fraud episode and other matters, the Journal reported. The agency has not publicly detailed the reported investigation.

Polymarket says it uses systems to identify suspicious activity and cooperates with regulators and law enforcement. Its market-integrity page says that more than 90 accounts were referred to authorities, along with details for more than 315 wallets.

The February fraud attempt has placed those safeguards under closer scrutiny as Polymarket expands its regulated U.S. business and considers a potential public listing.

Source: https://blockonomi.com/polymarkets-10m-fraud-attempt-puts-its-rapid-u-s-growth-under-scrutiny/