Brazilian Crypto Exchange Mercado Bitcoin Halts Trading After Cyberattack as Millions Leave the Platform

Mercado Bitcoin, which calls itself the largest digital assets investment platform in Latin America with about 4.5 million customers, suspended all deposits and withdrawals after a cybersecurity incident on Monday morning. Blockchain security companies said more than $46 million left the platform late on Sunday night. The company did not confirm that figure and did not respond to requests for comment.

In social media messages, Mercado Bitcoin said the attack did not harm customers or lead to a data breach, and that its teams are investigating, tracking the assets and working with authorities. It shared destination addresses for the stolen funds and pledged to restore the platform in the coming days. Several blockchain security experts disputed the claim that customer funds were untouched, pointing to blockchain evidence that funds were taken from some customer wallets. Tether's CEO said about $4.5 million was frozen, and other platforms froze a further $2 million. Chainalysis said it is tracking the coins to help the industry freeze and disrupt them.

The incident follows a theft of $6.3 billion from crypto platform Binance days earlier, which the FBI and U.S. Secret Service blamed on North Korean hackers. Multiple exchanges have lost millions over the past six months, and Chainalysis itself reported a breach last week in which attackers used AI-backed tools to access its systems and took user IDs, names, email addresses and role labels.