Key facts
- Mercado Bitcoin said about $38 million of assets were involved and that $11 million had already been blocked.
- Security firm Hypernative flagged more than $40 million in suspicious transfers across at least 10 blockchains.
- Arkham traced at least $46 million and Chainalysis about $49 million, with nearly $10 million frozen per Chainalysis.
- Tether CEO Paolo Ardoino said more than $4.5 million in USDT tied to the incident was frozen.
- Mercado Bitcoin said deposits and withdrawals remain suspended with no restart date.
- The exchange has not said how attackers got in or whether its $38 million figure includes frozen funds.
Mercado Bitcoin, Brazil's largest crypto exchange, said on November 3 that its customers will not bear the cost of a hack that hit its systems on November 2. The exchange said it identified and contained a security incident early that morning and suspended deposits and withdrawals as a preventive measure. It said no customer lost money and no data leaked, and it has not said how the attackers got in.
Estimates of the loss differ. Mercado Bitcoin put the value of the assets involved at about $38 million and said it had blocked $11 million after quick action with the crypto community and strategic partners, including Tether, Circle, Paxos, BRL1 and Chainalysis. It has not said whether that figure includes the frozen amount.
Security firm Hypernative flagged more than $40 million in suspicious transfers across at least 10 blockchains, including Bitcoin, Ethereum, Solana and Tron. Blockchain analysts at Arkham traced at least $46 million, while Chainalysis put the figure at about $49 million, with nearly $10 million frozen.
Tether CEO Paolo Ardoino said on X that more than $4.5 million in USDT, a token pegged to the dollar, had been frozen in connection with the incident. A freeze stops tokens from moving but does not return them to their owner.
Deposits and withdrawals remain suspended with no restart date. The exchange said it will post updates on X and resume service once full security is restored.
The incident follows an October 29 theft in which hackers drained more than $6 billion from Binance, the world's biggest exchange, an attack the FBI blamed on North Korea's TraderTraitor group. Mercado Bitcoin has not linked its incident to that attack. Binance CEO Richard Teng wrote on X that Binance would absorb the financial impact of the stolen funds rather than its users, adding that about 95% of the affected assets had been replenished.