Brazilian cryptocurrency exchange Mercado Bitcoin said it contained a security incident early on November 2 and temporarily suspended deposits and withdrawals while investigating the event. In a statement published through its official X account, the company said customers had not suffered losses and that no data had leaked. It also said teams were tracing assets and coordinating with authorities. Independent reporting linked the response to unusual transfers from wallets associated with the exchange across several blockchains, although Mercado Bitcoin did not publish an official loss figure or explain how the affected system was compromised.

The exchange's claims and the outside estimates

Mercado Bitcoin described the suspension as a precaution and said the incident had been contained. Those statements establish the company's position, but they do not resolve the size or ownership of the assets that moved. CoinDesk reported that security researchers estimated more than $40 million had left wallets tied to the platform across at least 10 networks. The report cited movements involving Bitcoin, Ethereum, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Smart Chain and Stellar. That estimate is not a figure confirmed by Mercado Bitcoin, and changing token prices or different wallet-labeling methods can produce different totals. CNN Brasil separately reported the company's assurance that clients were not harmed and data was not exposed.

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Asset tracing becomes the immediate operational priority

The exchange later shared destination addresses for several networks so other market participants could monitor the funds. CoinDesk also reported that Tether chief executive Paolo Ardoino said more than $4.5 million in USDT connected to the incident had been frozen. Freezing a stablecoin can limit movement of a specific asset, but it does not recover other tokens or explain how signing authority was obtained. There was no public attribution for the incident at the time of verification, and no evidence establishing a connection to other recent exchange attacks. Customers, counterparties and compliance teams therefore need to separate confirmed operational measures from researchers' evolving blockchain analysis.

Public service indicators improved later in the day

Mercado Bitcoin's public status page showed all listed systems operational when checked at 22:06 UTC on November 2. The page listed the website, registration, trading API, mobile app and login as operational after earlier notices had shown instability. However, it did not separately display the status of crypto deposits or withdrawals. The green service indicators therefore suggest that core user-facing systems had recovered, but they do not by themselves prove that every transfer function was restored or that the investigation was complete. Users should rely on the exchange's official communications for any account-specific restrictions.

Key questions remain unanswered

The incident leaves several material uncertainties: the exact value of assets affected, whether the transfers involved exchange capital or customer-linked balances, the technical path used to authorize them, and the timetable for a complete return to normal transfer operations. Mercado Bitcoin's pledge that customers were not harmed is important, but the financial effect on the company cannot be assessed without a fuller disclosure. The event also illustrates why a temporary service pause can be both a customer-protection measure and a sign that an exchange is still defining the scope of an incident. Further conclusions should wait for technical findings, audited figures or additional statements from the company and relevant authorities.

Sources

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