Mercado Bitcoin suspends deposits and withdrawals after $40 million security breach

Brazil’s leading cryptocurrency exchange, Mercado Bitcoin, temporarily halted customer deposits and withdrawals on Monday following a security incident identified in one of its internal systems. The company stated that it quickly contained the breach and assured users that customer funds remain intact and there was no data leak.

Exchange responds to security incident

In an official announcement on X, Mercado Bitcoin said, “We identified and quickly contained a security incident in one of our systems early this morning. As a preventive protection measure, deposits and withdrawals are temporarily suspended.” The company has not commented on how the attackers gained access to its systems.

Mercado Bitcoin emphasized it acted swiftly to prevent further impact, describing the suspension of deposits and withdrawals as a precaution to protect users while investigations continue.

The exchange disclosed the relevant destination wallet addresses across five networks—EVM chains, Bitcoin, Solana, Stellar, and Tron—enabling coordination with industry peers to help identify and monitor potentially suspicious fund flows.

Mini dictionary: Mercado Bitcoin is Brazil’s largest cryptocurrency exchange, serving millions of users and offering access to a wide range of digital assets in Latin America.

Blockchain security firms and Tether take action

Blockchain security firm Hypernative reported identifying more than $40 million across at least 10 blockchains in potentially suspicious transfers connected to the security incident. Hypernative’s preliminary analysis spanned networks such as Bitcoin, Ethereum, Solana, and Tron. Mercado Bitcoin has not confirmed this sum.

Paolo Ardoino, CEO of Tether, announced that the stablecoin issuer froze over 4.5 million $USDT linked to the flagged activity. According to Ardoino, this step aimed to prevent further movement of assets associated with the incident.

Ardoino explained that Tether is able to blacklist addresses holding $USDT if necessary, which prevents tokens from being transferred, even if it does not guarantee the recovery of the funds for the rightful owner.

$USDT, a dollar-pegged stablecoin, remains widely used for crypto trading, and Tether Inc. frequently coordinates with exchanges and authorities to address illicit activity involving its tokens.

Broader security concerns in crypto exchanges

The Mercado Bitcoin incident follows another major breach just days earlier, when hackers stole more than $6 billion from Binance, the world’s largest cryptocurrency exchange. The FBI has attributed the Binance attack to the North Korean group TraderTraitor. Binance stated that it has since resumed withdrawals and restored approximately 95% of affected assets.

Mercado Bitcoin has not linked its own security breach to the Binance incident. Investigations into the origins of the attack and the individuals responsible remain ongoing.

At the time of reporting, Mercado Bitcoin has not announced when deposits and withdrawals will resume. The exchange pledged to provide regular updates through its official channels on X.