Brazil's largest cryptocurrency exchange, Mercado Bitcoin, confirmed a security incident on Monday 2 November and temporarily suspended deposits and withdrawals as a precaution while its teams investigate.

The exchange said it had swiftly identified and contained the incident in one of its systems, and told customers there had been no loss to customers and no leak of customer data. It said it was tracking the assets involved and working with the relevant authorities.

More than $40m in suspicious transfers flagged

Blockchain security firm Hypernative flagged more than $40 million in suspicious transfers potentially linked to the incident, across at least 10 blockchain networks including Bitcoin, Ethereum, Solana and Tron. That figure is a preliminary assessment by the security firm and has not been confirmed by Mercado Bitcoin as a loss, so it should not be treated as a verified total.

Some Brazilian outlets cited estimates of around R$217 million from unnamed sources, and reported that Tether had frozen about $3.7 million linked to the attack. Neither figure has been confirmed by the exchange, and the method used to compromise the system has not been disclosed.

What customers should watch

The exchange has not said when normal deposit and withdrawal services will resume. Customers should rely on the exchange's own announcements rather than rumours on social media, and watch for any official update on the investigation before assuming the incident is closed.

Sources: Crypto Briefing, 2 November 2026; HokaNews, 2 November 2026.