Brazilian cryptocurrency platform Mercado Bitcoin suspended all deposits and withdrawals on Monday morning following a cyberattack, The Record reported. Blockchain security companies said more than $46 million left the platform late Sunday night, while the company said customers were unharmed—a claim disputed by researchers tracking the funds.
The suspension affects customers’ ability to move assets into or out of the platform. Mercado Bitcoin describes itself as Latin America’s largest digital assets investment platform, with about 4.5 million customers; that figure is its overall customer base, rather than a count of people whose funds were accessed.
In social media statements, Mercado Bitcoin said the attack had not caused a data breach or harmed customers. It did not confirm the reported loss figure and did not respond to The Record’s requests for comment, the publication reported.
Customer-wallet access disputed
Several blockchain security experts challenged the company’s assessment that customer funds had not been accessed. They pointed to transaction evidence on the blockchain—the shared ledger recording cryptocurrency movements—that they said showed attackers siphoning funds from some customer wallets.
That disagreement matters to customers awaiting access to their assets: the company’s assurances and the researchers’ findings give different accounts of whose funds were reached. The reported transfers began late on Sunday before Monday morning’s suspension.
Mercado Bitcoin said its teams were investigating, tracking assets and coordinating measures with the authorities. It also shared destination addresses for the stolen funds, allowing other participants in the cryptocurrency industry to identify where the assets had moved.
Platforms freeze some of the stolen cryptocurrency
Tether CEO Paolo Ardoino said Tether had frozen about $4.5 million stolen from Mercado Bitcoin. Other platforms froze another $2 million worth of cryptocurrency, The Record reported. Freezing those assets is a containment step; the reported figures describe funds frozen, rather than money returned to customers.
Blockchain security company Chainalysis said its investigators were tracking the coins to help the industry identify, freeze and disrupt the affected funds.
The incident follows several cryptocurrency exchange attacks over the past six months, including multiple losses exceeding $100 million and a reported $6.3 billion theft from Binance days earlier that the FBI and U.S. Secret Service attributed to North Korean hackers. Chainalysis itself announced an incident the previous week in which attackers used AI-backed tools to access its systems and internal tools, stealing platform users’ IDs, names, email addresses and organization role labels.
For Mercado Bitcoin customers, deposits and withdrawals remain the immediate operational issue. The company pledged to restore the platform in the coming days while its teams continue investigating and tracking the assets.
