Polymarket Halts Trading After Breach With $2.7 Million Loss Estimate

Polymarket halted trading on its international platform Thursday after a breach involving an outside service provider led to unauthorized withdrawals from user accounts, with losses estimated at about $2.7 million.

The affected accounts held balances on the international venue. Polymarket identified a compromised provider as the source of the breach and said it had fixed the issue.

The company referred the incident to law enforcement and pledged to compensate affected users. Reports of unauthorized withdrawals appeared on X before Polymarket disclosed the breach Thursday.

The incident is Polymarket's second third-party breach involving user losses in recent months. A separate vendor compromise in June affected the platform's front end and resulted in about $3 million being stolen from users.

The estimated loss for the October breach is below June's approximate loss. The two incidents involved different parts of Polymarket's service: the international venue in October and the front end in June.