Brazil's Largest Exchange Mercado Bitcoin Halts Withdrawals After $40 Million Hack

In brief

• Mercado Bitcoin suspended deposits and withdrawals on Monday after a security incident, saying customers lost nothing and no data leaked.
• Blockchain security firm Hypernative flagged more than $40 million in suspicious transfers across at least 10 blockchains; the exchange has not confirmed that figure.
• Tether CEO Paolo Ardoino said the stablecoin issuer froze more than 4.5 million USDT tied to the incident.

Brazil's largest crypto exchange, Mercado Bitcoin, suspended deposits and withdrawals on Monday after identifying a security incident in one of its systems in the early hours of the morning. The exchange said no customer lost money and no data leaked.

"We identified and quickly contained a security incident in one of our systems early this morning," Mercado Bitcoin said in a Portuguese-language statement on X. "As a preventive protection measure, deposits and withdrawals are temporarily suspended."

Blockchain security firm Hypernative flagged more than $40 million in suspicious transfers that may be linked to the incident, according to a preliminary analysis that spans at least 10 blockchains, including Bitcoin, Ethereum, Solana, and Tron. Mercado Bitcoin has not confirmed that figure and has not disclosed how the attackers got in.