Mercado Bitcoin Suspends Deposits and Withdrawals After Security Incident

Mercado Bitcoin halts platform transfers

Mercado Bitcoin, Brazil’s largest cryptocurrency exchange, kept deposits and withdrawals suspended on Monday after identifying a security incident in one of its systems. The halt prevents customers from moving funds into or out of the platform while the company works to restore operations. The exchange described the interruption as a precaution, rather than announcing a permanent service change, but has not said when transfers will resume.

In a statement posted to X, Mercado Bitcoin said it had identified and contained the incident. It also said customers had suffered no losses and that no data had leaked. Those statements offer the company’s current assessment, but the exchange has not published technical details that would explain which system was affected or how the incident unfolded. The scope and method of the breach therefore remain unknown from the information disclosed so far.

The company said its teams were investigating, tracing assets and coordinating with authorities. Bloomberg reported that Mercado Bitcoin said it would absorb all losses. That assurance is distinct from a confirmed accounting of the incident: the exchange has not provided a total loss figure, specified how much was taken, or confirmed the preliminary estimates circulating among outside observers. Its public updates also do not set a timetable for restoring deposits and withdrawals.

What the exchange has disclosed

The exchange’s lack of a confirmed transfer total leaves an important gap in the public picture. The source account says Mercado Bitcoin has not identified the system involved, disclosed how much may have been taken, or stated a reopening date. Its assurances about customers and data are relevant, but do not resolve those unanswered questions. Until the company provides further details, the incident’s technical scope and operational consequences cannot be established from its statements.

Mercado Bitcoin has published destination addresses associated with transactions it linked to the incident. The addresses cover Bitcoin, Ethereum-compatible networks, Solana, Stellar and Tron, and the company said it shared them to support identification and tracking. Publishing wallet destinations gives investigators and other market participants specific transactions to examine. It does not, by itself, establish the total value involved or show that funds have been recovered.

Blockchain security firm Hypernative has placed preliminary estimates of suspicious transfers above $40 million across several blockchains. Mercado Bitcoin has not confirmed that figure, so it should not be treated as an official loss total. The source also notes that other analysts have cited higher amounts and that transfers were still being swept. These differences underline that estimates may change as wallet activity is examined and the exchange provides more information.

Tracking activity across blockchains

Tether has joined the response by freezing more than 4.5 million USDT linked to the incident, according to CEO Paolo Ardoino, who posted the figure on X at 10:06 a.m. ET. The freeze is a concrete action involving identified stablecoin funds, but the source does not say what share of the suspected transfers it represents or whether the assets will ultimately be returned. Those outcomes remain unresolved.

Tether’s involvement has an existing commercial connection: the company invested $20 million in Mercado Bitcoin in July. At the time, Tether said the exchange served 4.5 million users. The investment and user figure provide context for the relationship between the firms, while the reported USDT freeze shows Tether’s role in this response. The source does not indicate that the investment is related to the security incident or its investigation.

The incident follows another major exchange security event described in the source. On Oct. 29, attackers reached $6.3 billion in assets at Binance after compromising an engineer’s laptop and accessing internal systems used to process withdrawals. Binance said it found no evidence that private keys were exposed. The comparison places Mercado Bitcoin’s service suspension amid heightened attention to exchange security, but the source does not establish a connection between the incidents.

A wider security backdrop

Binance said that by Nov. 1 it had replaced 95 percent of the stolen assets and had begun restoring withdrawals in phases. The source reports that the FBI attributed the attack to North Korea, while the U.S. Secret Service worked with Circle to trace and freeze funds. Tether reported about $1.57 billion in USDT frozen, and Circle said it had frozen more than $800 million in USDC in coordination with authorities. These details concern the separate Binance case.

The Binance response also remained incomplete in the account provided. The exchange said it found additional breach points beyond the initially identified engineer’s laptop compromise, but had not released a full post-mortem on how the operation was prepared and carried out. Some estimates put the groundwork at at least 36 hours. The destination of roughly $3.3 billion in funds that were not frozen was still unexplained, and Binance had not detailed expected recovery from that pool.

Investigators in the Binance case were continuing to track wallet activity across ten blockchains, according to the source. For Mercado Bitcoin, the immediate public facts are narrower: transfers remain suspended, the company says it contained the incident, and it has provided addresses to aid tracking. The preliminary estimate above $40 million is not exchange-confirmed, while the affected system, final amount and reopening schedule have not been disclosed. Further updates will be needed to clarify those points.

Source: BitcoinMagazine