Polymarket Halted International Trading After Hackers Drained Accounts

The hack affected Polymarket’s flagship international platform, but not Polymarket’s own website directly. A third-party vendor based in the United Kingdom was breached, and money was drained from some traders’ wallets. UK law enforcement was notified. Polymarket temporarily halted trading while it investigated the incident, helping the company assess the damage and protect the platform while activity was paused.

Blockchain analytics firm Bubblemaps estimated that about 700 users were affected and approximately $2.7 million was stolen. Prominent traders also reported losses on X. The article does not identify the vendor’s exact access route or explain precisely how each wallet was reached. It does establish that the vendor breach enabled the theft.

Trading has now resumed on the international platform. Polymarket says it will refund affected traders, although it declined to provide its own figures for the number of victims or total losses. The incident adds to earlier security concerns, including another breach in June 2026 that caused more than $2 million in losses.

A prediction market is a trading platform where participants express views about future events. Instead of buying company shares, traders take positions linked to outcomes, such as whether a political, economic, or other event will occur. Prices can reflect the market’s collective expectations, while traders use their positions to wager on what they believe will happen.

For example, a trader might buy a contract connected to a future event. If the event occurs as expected, the position may produce a payout under the platform’s rules. If the prediction is wrong, the trader can lose money. The source identifies Polymarket’s flagship platform as a cryptocurrency-based prediction market, but it does not give a specific contract example from this incident.

Polymarket runs two separate markets. Its international platform uses cryptocurrency and is banned in the United States and several other countries. Polymarket US operates as a federally regulated financial exchange for people within the United States, so traders there use a different platform under different rules.

The apparent scale of the hack was about 700 affected users and approximately $2.7 million in stolen funds. Those estimates came from Bubblemaps, a blockchain analytics firm that examined activity connected with the breach. The figures show that the incident reached many traders and caused substantial financial damage, even though the article does not describe it as a compromise of Polymarket’s website itself.

Prominent traders publicly complained on X that they had lost money. Their reports helped draw attention to the incident, while the blockchain analysis supplied estimates for the number of affected users and the amount stolen. Polymarket declined to comment when WIRED asked how many traders were impacted and how much was lost.

The company did say it would refund affected traders. Trading was initially paused for several hours, then resumed. The final amount of loss and final victim count could differ from the early estimates, because Polymarket has not publicly confirmed those figures in the source.

A third-party breach can cause financial harm when a vendor handles services connected to a platform’s users, transactions, or wallets. Attackers do not necessarily need to break into the main website if the vendor has trusted access to related systems. Compromising that outside connection can create a path to funds or wallet operations.

In this case, the article says a UK-based third-party vendor was breached and that money was drained from some traders’ wallets. It does not identify the vendor’s role, the credentials involved, or the exact technical mechanism. Therefore, the precise route from the vendor breach to the stolen funds is not established by the source.

The distinction still matters. Polymarket says its website was not hacked, yet traders were affected through a weakness elsewhere in its service network. The company paused trading, notified UK law enforcement, investigated for several hours, and later promised refunds before resuming international trading.

Polymarket says it will refund traders affected by the breach. That promise is the immediate remedy for people whose wallet funds were stolen, although the source does not provide a timetable or explain the refund process. Trading on the flagship international platform has already resumed after being paused for several hours during the investigation.

The pause gave Polymarket time to examine the incident after a UK-based third-party vendor was breached. Bubblemaps reported that about 700 users appeared affected and approximately $2.7 million was stolen. Polymarket declined to confirm those numbers, so the company’s final accounting remains undisclosed in the source.

The platform now continues operating, but the incident adds to its security history. Another breach in June 2026 caused more than $2 million in losses for affected traders. Refunds may help restore confidence, while the repeated incidents increase attention on how Polymarket and its vendors protect traders’ funds.

The two services operate under different legal structures. Polymarket’s flagship international platform is cryptocurrency-based and operates separately from Polymarket US. Polymarket US is described as a federally regulated financial exchange for people within the United States. That separation means users in the United States access a different product from international traders.

The source states that the flagship platform is banned in the United States and a number of other countries. It does not identify a specific statute or give a detailed legal explanation for the ban. Therefore, the article supports the distinction between the platforms and their regulatory treatment, but not a more precise reason for the prohibition.

The split also mattered during this hack. The breach affected traders on the international platform, while Polymarket said Polymarket US users were not impacted. Separate operations and rules can limit an incident’s reach, though the article does not explain the technical boundaries between the two systems.

A cryptocurrency wallet is a digital tool or account that lets a person control and transfer cryptocurrency on a blockchain. It works through cryptographic credentials, commonly called private keys or equivalent access controls. The wallet does not necessarily store coins in one physical place; it enables control over blockchain funds.

If an attacker gains the ability to authorize a transfer, funds can move to another blockchain address. Blockchains record those transactions, but the source does not describe a built-in reversal process. Recovery may therefore be difficult, especially if the recipient is unknown or moves the funds again. The article does not explain the exact wallet technology involved in this breach.

That difficulty makes Polymarket’s refund promise important for affected traders. Bubblemaps estimated that approximately $2.7 million was stolen from around 700 users. Polymarket paused trading, investigated, and later resumed the service, while saying it would refund impacted traders.