Polymarket freezes international trading after DebugBear hack drains accounts

Polymarket halted trading on its international exchange on Thursday after a security breach in a third-party service led to unauthorized withdrawals. The company identified DebugBear, a website performance monitoring platform based in the United Kingdom, as the source of the intrusion. Polymarket has referred the case to U.K. law enforcement agencies.

Traders first reported seeing missing funds on social media platforms during the afternoon. In response, the prediction market suspended operations on its global platform. Polymarket stated that it repaired the issue on its end and resumed trading at 3 p.m. Eastern Time. The company confirmed that its separate U.S. platform was not compromised by the incident.

Data from analytics firms Betting Intelligence and Polysights indicates the scale of the theft. An account on Polymarket moved at least $2.7 million across 710 other wallets on Thursday. The firms provided this analysis of publicly available blockchain data to CNBC. It is currently unclear how many total users lost funds in the attack.

Polymarket pledged to reimburse any affected traders. A person familiar with the matter noted that the company has already contacted law enforcement regarding the breach. DebugBear posted on X that it experienced a security incident on Thursday but did not immediately respond to a request for comment.

The international exchange operates as a decentralized finance platform on the Polygon blockchain. It is not regulated in the United States. This disruption occurred days before the U.S. midterm elections on Nov. 3, a period when both the international and U.S. exchanges typically see heightened trading volumes.

A similar incident occurred in June when a third-party vendor was compromised. At that time, Polymarket also announced it would refund affected users.