Scammers tried to swipe at least $10 million from Polymarket by funding accounts with stolen debit cards. The scheme involved topping up balances, making trades, and then attempting to cash out to other cards or bank details they controlled.

What Happened

The attack kicked off in February and centered on about seven accounts. One of these accounts alone saw roughly 4,000 deposit attempts — the bad actors were clearly trying to move funds in fast, trade, and withdraw before getting caught.

How the Scam Worked

The group used stolen debit card info to load up Polymarket accounts, then executed trades. After that, they tried to withdraw the funds to different cards or accounts under their control, hoping to launder the money before anyone noticed.

The Payment Processor's Role

Checkout.com, which handles payments for Polymarket US, started flagging and blocking more than 80% of all incoming deposits at one point, marking them as fraudulent. This highlights just how aggressive and large-scale this wave of suspicious activity was.

Polymarket and its payment partners faced a coordinated push to exploit fiat onramps using stolen cards. There’s no info yet on the final losses or what actions Polymarket or the scammers took after the fact.