Brazil's Largest Exchange Mercado Bitcoin Halts Withdrawals After $40 Million Hack
In brief
- Mercado Bitcoin suspended deposits and withdrawals on Monday after a security incident, saying customers lost nothing and no data leaked.
- Blockchain security firm Hypernative flagged more than $40 million in suspicious transfers across at least 10 blockchains; the exchange has not confirmed that figure.
- Tether CEO Paolo Ardoino said the stablecoin issuer froze more than 4.5 million USDT tied to the incident.
Brazil's largest crypto exchange, Mercado Bitcoin, suspended deposits and withdrawals on Monday after identifying a security incident in one of its systems in the early hours of the morning. The exchange said no customer lost money and no data leaked.
"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."
Blockchain security firm Hypernative flagged more than $40 million in suspicious transfers that may be linked to the incident, according to a preliminary analysis that spans at least 10 blockchains, including Bitcoin, Ethereum, Solana, and Tron. Mercado Bitcoin has not confirmed that figure and has not disclosed how the attackers got in.
In a follow-up post, the exchange published the destination addresses it identified on five networks: EVM chains (blockchains built to run the same code as Ethereum), Bitcoin, Solana, Stellar, and Tron. It said the addresses were released only so others can identify and track the funds on-chain.
Comunicado oficial:
Identificamos e contivemos com rapidez um incidente de segurança em um de nossos sistemas nesta madrugada.
Reforçamos que:
• Não houve nenhum prejuízo aos clientes;
• Não houve vazamento de dados.Como medida preventiva de proteção, depósitos e saques…
— Mercado Bitcoin (@MercadoBitcoin) November 2, 2026
Tether CEO Paolo Ardoino said in a post on X that the stablecoin issuer has frozen more than 4.5 million USDT connected to the incident.
USDT is a dollar-pegged stablecoin, and Tether can blacklist the addresses holding it so the tokens cannot be moved, though a freeze does not by itself return the funds to their owner.
Tether froze more than 4.5M USDT related to this security incident. https://t.co/PCtP4957jn
— Paolo Ardoino 🤖 (@paoloardoino) November 2, 2026
The incident comes 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 since reopened withdrawals and said it replenished about 95% of the affected assets. Mercado Bitcoin has not linked the two incidents and has not said who is behind its own.
Deposits and withdrawals at Mercado Bitcoin remain suspended, and the exchange has not given a date for resuming them. It said it will post regular updates on X.
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