Polymarket Halts Trading After Third-Party Security Breach

Polymarket suspended trading on its international platform for nearly an hour on Thursday after a third-party software provider suffered a security breach. The company stated that the incident forced it to take the site offline temporarily to secure user funds.

According to a person familiar with the details, the attackers accessed funds through DebugBear, a web analytics tool. DebugBear confirmed on X that it was experiencing an ongoing security incident at approximately 2 p.m. ET. Polymarket said the attack appeared to originate from the United Kingdom and that the matter has been referred to British law enforcement.

The platform promised that any user who lost money would be compensated. In a post on X, the company stated, “We’ll make this right and are fully reimbursing all affected traders.” Earlier in the day, Polymarket added that “anyone who has been impacted will be made whole.” The company did not confirm the total amount of money lost in an initial statement.

Crypto news website The Block reported that approximately $2.65 million in cryptocurrencies was siphoned from user wallets. This figure comes from data provided by blockchain analysis group Arkham. A representative for Polymarket declined to comment on that specific number or the precise nature of the attack.

Trading resumed at 3 p.m. ET after the outage. The company said it had identified and fixed the issue affecting Polymarket.com. The U.S.-based version of the platform did not appear to be affected by the breach. Users on the company’s Discord channel reported that their wallets had been drained, though these reports were not immediately confirmed by the company.

Polymarket is currently valued at $21 billion following a $1 billion investment led by Donald Trump Jr. in September. The platform processes about $200 million in trading activity daily. The company is also investigating suspicious betting activity related to the U.S. midterms and Israel’s elections. Shana Bautista, head of global intelligence and investigations at Polymarket, said the team is looking into dozens of bets tied to the midterm races.

The breach occurred as prediction markets face increased scrutiny. U.S. states and the Trump administration are engaged in a dispute over the regulation of betting on these platforms. Polymarket and rival Kalshi are both navigating these regulatory challenges while managing potential insider trading concerns.