Mercado Bitcoin, Brazil’s largest crypto exchange, hit by $46 million security breach

Judgment

Mercado Bitcoin’s incident-response team now owns the call on when to reopen deposits and withdrawals: restoring access quickly limits client disruption but risks letting attacker-linked flows out before forensics and law-enforcement coordination are complete.

Basis

Mercado Bitcoin said it “identified and swiftly contained” a security incident in one of its systems and paused deposits and withdrawals as a precaution; Arkham data put the affected assets at about $46.3 million. Arkham analyst Emmett Gallic said the attacker was sweeping funds from older deposit addresses and selling memecoins and altcoins. Tether CEO Paolo Ardoino confirmed Tether froze more than 4.5 million USDT linked to the incident. The exchange said customers were not affected and no data breach occurred, and it published destination wallet addresses for tracking. The mechanism is a containment tradeoff: pausing transfers cuts off attacker exit routes and preserves forensic evidence, but it also blocks legitimate client liquidity until teams track assets and coordinate with authorities.