Polymarket Halted International Trading After Hackers Drained Accounts

Polymarket temporarily suspended trading on its flagship international prediction-market platform after a breach at an unnamed UK-based third-party provider exposed traders’ wallets and led to funds being stolen. The company said its own website was not hacked, notified UK law enforcement, and resumed trading after investigating for several hours. Blockchain analytics firm Bubblemaps estimated that about 700 users were affected and roughly $2.7 million was taken; Polymarket did not confirm those figures but promised to reimburse affected traders. The incident did not affect Polymarket US, a separate platform operating as a federally regulated exchange for customers in the United States.

The breach adds to security concerns surrounding the cryptocurrency-based international service: traders also lost more than $2 million in a June 2026 incident. Polymarket, launched in 2020, has drawn scrutiny beyond cybersecurity, including alleged insider-trading cases involving a soldier accused of betting on the capture of Venezuela’s former leader and a Google employee accused of profiting from confidential information. Both defendants have pleaded not guilty. Despite these controversies, the company raised $1 billion in August 2026 in a round led by a firm associated with Donald Trump Jr., reaching a reported valuation of $21 billion. The episode highlights the risks users face when trading through a platform that relies on outside providers, even as Polymarket says it will cover the latest losses.