TLDR Polymarket restored trading on its international platform after a security breach at a third-party vendor on October 29. Bubblemaps estimates about $2.7 million was stolen from roughly 7
Polymarket has restored trading on its international platform after a security incident at an outside service provider on October 29. The company says traders who lost money will be fully reimbursed.
Blockchain analytics firm Bubblemaps estimates that about $2.7 million was stolen. Polymarket has not confirmed that figure.
Polymarket first moved its exchange into cancel-only mode. This let customers withdraw existing orders while new trades stopped processing.
The company also paused the service that submits transactions on behalf of users. It then reported that one of its third-party providers had been compromised.
Trading stayed paused for several hours while the company investigated. A later update from the Polymarket Traders account on X confirmed that trading was fully back online.
The company said the breached vendor is based in the United Kingdom. Polymarket said its own website was not breached and that UK law enforcement has been notified.
The hack did not affect Polymarket US. That newer platform operates as a federally regulated exchange for people in the United States.
The flagship international platform is cryptocurrency-based. It is banned in the United States and several other countries.
Bubblemaps traced funds from hundreds of deposit wallets into an address it identified as belonging to the attacker. Its diagram showed 712 deposit wallets and about $2.71 million moving through the main route.
Polymarket Drain Report
A third party provider from Polymarket was compromised
700+ users drained and $2.7M stolen
Main attacker:0x3F99139F1C5854bb628c2e576Aaf638e99dFfc18
Funds converted to $POL and sent out to:
$1.4M0xe4C4C39C1733e1C7c06B79f97ED442B68Df41EC6
$523k… pic.twitter.com/XF7Cxz2GdH
— Bubblemaps (@bubblemaps) October 29, 2026
The firm said the funds were converted into POL, the native token of Polygon, and sent to several addresses. It also tracked transfers to Ethereum.
Researchers linked suspicious code to a website performance-monitoring service. These tools normally help companies see how their websites load and work.
According to the researchers, malicious code accessed users’ trading sessions and started actions that moved assets out of their accounts. The exact attack method is still under investigation.
On X, several prominent traders said they had lost money. Polymarket declined to tell WIRED how many traders were affected or how much was lost.
This is not the platform’s first breach. In June 2026, another incident led to more than $2 million in losses for affected traders.
The company has faced controversy since its 2020 launch, including alleged insider trading cases that led to arrests. In those cases, the suspects have pleaded not guilty.
In August 2026, Polymarket raised $1 billion in a funding round led by 1789 Capital, where Donald Trump Jr. is a partner. The company is now valued at $21 billion.
Polymarket has promised full repayment but has not shared a timeline or claims process. Users are waiting for details on which accounts qualify, how losses will be calculated and when funds will be returned. A full analysis of the incident is expected from the Polymarket team.
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