Polymarket Suspends Trading as Third-Party Breach Triggers User Losses

Polymarket has paused trading on its international platform after a compromised third-party provider exposed users to unauthorized fund withdrawals.

The prediction market company disclosed the security issue on Thursday after multiple users posted complaints on X (formerly Twitter), claiming that assets had been transferred out of their accounts without approval. CoinDesk confirmed that some customers holding funds on Polymarket’s international platform had their balances drained.

In a notice shared through its status page, Polymarket said it had located and fixed the issue affecting the international service. The company traced the incident to a breach at one of its external providers and said the matter had been handed over to the relevant law enforcement agencies.

The platform assured users that those affected would be compensated for their losses. Trading, however, remained suspended following the incident.

This is the second time in recent months that a security failure at an outside provider has led to financial losses for Polymarket customers.

A similar incident occurred in June when another third-party vendor was compromised, affecting the platform’s front-end systems. Around $3 million in user funds were lost in that attack.

DeFiLlama’s tracking data estimates that Thursday’s breach resulted in approximately $2.7 million in losses, narrowly below the amount reported in June.

The report was updated on October 29, 2026, at 19:33 UTC to include additional information and at 19:39 UTC to revise the estimated financial impact.