Mercado Bitcoin froze deposits and withdrawals on Monday, November 2, following a breach of one of its systems.
The exchange, which is the largest in Brazil, says no customer lost money and that it will cover the losses itself. Outside analysts say that the total loss is north of $40 million.
When did Mercado Bitcoin detect the breach?
The company said the intrusion happened overnight and was contained quickly. In a statement written in Portuguese on X, Mercado Bitcoin told users that no funds were lost and no data was exposed.
The company said that the pause on transfers was a precaution while it continues to investigate the hack.
Not long after the first post, Mercado Bitcoin dropped another update on X , stating that it was still working on bringing operations back safely. It added that it would update customers through official channels.
The exchange also published the destination wallet addresses that it linked to the bad actors. The cover includes Bitcoin, Ethereum-compatible networks, Solana, Stellar and Tron, with the company saying they shared the list so others could trace the stolen assets on-chain.
So far, the exchange has not confirmed any exact figure in terms of what was lost, and it has not released a timeline for when trading will resume.
However, the company reportedly told its users that it would absorb all losses.
Analysts put the haul above $40 million
While Mercado Bitcoin has not said anything in terms of the amount that was lost, others have.
Security firm Hypernative flagged more than $40 million in suspicious transfers that may tie to the incident, spread across at least 10 blockchains, including Bitcoin, Ethereum, Solana and Tron.
The estimates are moving higher as the attacker keeps working. Arkham analyst Emmett Gallic said that the losses are already above $46 million and are climbing. “Lots of old deposit addresses are being swept by the hacker currently, while they sell off memecoins and altcoins,” Gallic said.
Tether steps in to freeze funds
Stablecoin issuer Tether is one of the major external parties that have joined the response to curb the theft. Its CEO Paolo Ardoino wrote on X that the company had frozen more than 4.5 million USDT linked to the breach.
Also, the USDT issuer has a direct stake in the outcome. In July, it put $20 million into a growth round for Mercado Bitcoin, a licensed platform that Cryptopolitan reported serves 4.5 million users across Latin America and holds more than 10 licenses across Brazil and Europe. Ardoino called the firm’s licensing and tokenization reach “unmatched in Latin America” at the time.
A second major exchange hit in a week
The industry is still yet to shake off the recent Binance exploit that has gone on record to be the largest heist in the history of crypto.
The Binance hack, which occurred on October 29, saw attackers drain about $6.3 billion. Binance said that the attackers were able to wreak havoc by having compromised a DevOps engineer’s laptop and reaching an internal service container used to push withdrawals. The FBI blamed North Korea’s TraderTraitor operation.
Binance leadership moved swiftly to inform users that their SAFU fund and reserves would cover user losses, and it made good on its promise of reopening withdrawals in 48 hours, which fell on November 1.
Users pulled a net $3.64 billion, or 2.1% of the exchange’s assets, once transfers resumed. Across that case, Tether froze about $1.567 billion in USDT, and Circle froze more than $1.1 billion in USDC.
Reports say that the run of attacks this year, from Polymarket to South Korean and Japanese financial firms, has fed concern that AI tools are making hackers more effective at reconnaissance and social engineering.
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