Polymarket has resumed trading on its international platform following a suspension due to a security incident involving a third-party service provider. The halt in trading occurred on October 29 after several users reported unauthorized withdrawals from their accounts. The company has acknowledged the breach and assured that all affected users would be reimbursed for their losses.
An investigation into the incident is underway by UK authorities, but Polymarket has not disclosed the specific financial impact of the breach. Reports indicate that approximately 700 users may have been affected, leading to an estimated total loss of around $2.7 million, according to blockchain analytics firm Bubblemaps.
Investigators have identified DebugBear, a website performance monitoring service, as the compromised third-party vendor. DebugBear recognized the breach and notified its clients to remove code associated with its services from their websites.
Despite the significant breach, the exact method of compromise and the total extent of the damage remains undisclosed. After a temporary investigation period, trading activities resumed on Thursday following resolution of the issues.
While Polymarket has committed to compensating the affected users, details on how many accounts were compromised or the total compensation amount have yet to be revealed. Notably, the incident did not impact Polymarket’s separate platform for users in the US.
This breach marks another security challenge for Polymarket, following a previous incident in June 2026 when hackers used an external service provider to access applications and siphon off about $3 million from user accounts. The current incident highlights the potential risks associated with third-party software services, where vulnerabilities can compromise user data even if the main platform's security remains intact. Polymarket continues to investigate the latest breach while promising to cover the losses of affected traders.
