Mercado Bitcoin Halts Withdrawals After Possible $40 Million Hack
MB says customers did not suffer losses, but Hypernative estimates the possible damage at $40 million. The suspicious transfers moved across multiple blockchains, including Bitcoin and Ethereum.
Key Takeaways
- Mercado Bitcoin temporarily paused deposits and withdrawals after a possible security incident.
- The company says customers did not suffer losses and that no data breach has been reported.
- Hypernative estimates the possible damage at about $40 million and saw suspicious transfers on at least ten blockchains.
Mercado Bitcoin, Brazil's largest crypto exchange, has temporarily paused deposits and withdrawals after a possible security incident. The crypto company says customers did not suffer losses and that there was no data breach, while blockchain security firm Hypernative estimates the possible damage at about $40 million (€35.7 million).
What MB Says Itself
According to Mercado Bitcoin, the incident was quickly contained overnight in one of its systems. The company says it is now tracing the affected assets and working with the relevant authorities. It is still not known when deposits and withdrawals will reopen.
The exchange stressed that the measure was taken as a precaution. The statement also says the investigation is ongoing and that more updates will follow later.
What Hypernative Saw
Hypernative said that the suspicious activity started around 11:00 p.m. on Sunday night, Brazil time. According to the security firm, wallets from MB were active on at least ten blockchains, including Bitcoin, Ethereum, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Smart Chain, and Stellar.
Notably, the transfers do not appear to be an attack through smart contracts. They were ordinary crypto transfers that were signed as if they had been authorized by the source wallets themselves. How the attacker got that signing ability is still unclear.
Why This Matters More Broadly
The timing makes the incident especially sensitive for the crypto market. Just a few days earlier, Binance was hit by a much larger hack, in which, according to earlier reports, about $6.3 billion in digital assets was stolen. Incidents like that put wallet security, key management, and the question of how quickly exchanges can slow down suspicious money flows back in the spotlight.
For European crypto followers, what matters most is that cases like this are not just about one exchange. They also show how quickly problems can spread across multiple chains and how important fast coordination between exchanges, security firms, and authorities is. Even earlier incidents were about quick responses to suspicious wallet movements, like the Binance hack where withdrawals were paused.