Mercado Bitcoin Pauses Withdrawals as $40 Million in Suspected Transfers Go Off-Grid

Mercado Bitcoin suspended deposits and withdrawals on November 2, 2026, after identifying a security incident in one of its systems, while blockchain security firm Hypernative detected more than $40 million in suspicious transfers linked to exchange wallets. The exchange said, “There was no loss to clients; There was no data leak.”

“We identified and quickly contained a security incident in one of our systems early this morning,” Mercado Bitcoin said in a Portuguese-language statement on X. “As a preventive protection measure, deposits and withdrawals are temporarily suspended.” The company said teams were investigating, tracing the assets and coordinating with competent authorities, but provided no timeline for restoring services or confirmed Hypernative’s estimate.

Hypernative’s preliminary analysis identified suspicious movements across at least 10 blockchains, including Bitcoin, Ethereum, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Smart Chain and Stellar. The first movements appeared around 11 PM Sunday night in Brazil. Wallets attributed to MB transferred funds mainly to newly created addresses linked to the possible attacker through ordinary cryptocurrency transfers signed as if authorized by the source wallets, rather than through an exploit of smart contracts. Hypernative said it remained unclear how the attacker obtained the signing capability.

Mercado Bitcoin subsequently published destination addresses on five network types—EVM chains, Bitcoin, Solana, Stellar and Tron—solely to allow the funds to be identified and tracked on-chain. The exchange did not directly connect its reported “overnight” incident to the transfers, and the origin of the incident, the total amount lost, whether the assets belonged to clients or the exchange, and the identity of the attacker remained undisclosed.

Tether CEO Paolo Ardoino said on X that Tether had frozen more than 4.5 million USDT connected to the incident. A freeze prevents the tokens from being moved but does not itself return them to their owner. The incident came days after hackers drained more than $6 billion from Binance on October 29, a theft the FBI attributed to North Korea’s TraderTraitor group. Binance has reopened withdrawals and said it replenished about 95% of the affected assets, while Mercado Bitcoin maintained its suspension and said it would publish regular updates on X.