Brazil’s largest cryptocurrency exchange, Mercado Bitcoin, kept deposits and withdrawals suspended on Monday after identifying a security incident in one of its systems. The measure prevented customers from moving funds into or out of the platform while the company worked to restore operations.
In a statement posted to X, Mercado Bitcoin said it had contained the incident and that customers had suffered no losses. The company also said no data had leaked and described the suspension as a precaution. Its teams are investigating, tracing assets and coordinating with authorities. According to Bloomberg, the exchange said it would absorb any losses.
Mercado Bitcoin has not disclosed which system was affected, how much was taken or when deposits and withdrawals will resume. Its public statements have not provided a total loss figure or a reopening timetable.
The exchange published destination addresses associated with transactions from the incident involving Bitcoin, Ethereum-compatible networks, Solana, Stellar and Tron. It said the addresses were shared to support identification and tracking efforts. Hypernative has estimated that suspicious transfers exceeded $40 million across several blockchains, but Mercado Bitcoin has not confirmed that amount. Other analysts have cited higher figures while the movement of assets remains ongoing.
Tether is also participating in the response. Tether CEO Paolo Ardoino said on X that the company had frozen more than 4.5 million USDT linked to the incident. Tether invested $20 million in Mercado Bitcoin in July, when it said the exchange served 4.5 million users.
The incident follows a major cryptocurrency theft involving Binance on October 29. Attackers accessed $6.3 billion in assets after compromising an engineer’s laptop and reaching internal systems used to process withdrawals. Binance said private keys were not exposed and reported by November 1 that it had replaced 95 percent of the stolen assets and begun restoring withdrawals in phases.
The FBI attributed the Binance attack to North Korea, while the U.S. Secret Service worked with Circle to trace and freeze funds. Tether reported freezing approximately $1.57 billion in USDT, and Circle said it had frozen more than $800 million in USDC in coordination with authorities. Investigators are continuing to track wallet activity across ten blockchains.
Sources: Bitcoin Magazine.