Mercado Bitcoin Halts Withdrawals After Security Incident as Hypernative Flags $40M Outflows

Mercado Bitcoin, one of Latin America's largest crypto exchanges, has halted withdrawals following a security incident, with on-chain security firm Hypernative flagging roughly $40 million in outflows from the platform. Tether has since blacklisted two attacker addresses on Ethereum and Tron, freezing the USDT held in them, though the exchange has not disclosed the full scope of the breach. The halt affects customer funds across the exchange, and the involvement of stablecoin issuer blacklisting tools suggests a portion of the stolen assets may be recoverable. The incident adds to a string of 2025 exchange security failures and puts pressure on Mercado Bitcoin's solvency and custody practices. Watch for whether the exchange restores withdrawals, discloses the total loss amount, and whether further frozen funds are identified as stolen USDT moves across chains.