Mercado Bitcoin Halts Withdrawals Over Security Incident as Hypernative Flags $40 Million Drain

Mercado Bitcoin, one of Brazil's largest cryptocurrency exchanges, has halted withdrawals following a security incident, with on-chain monitoring firm Hypernative flagging more than $40 million in outflows from wallets it attributes to the exchange. The company says no client funds were lost, though the discrepancy between that claim and the observed drain will be a key point of scrutiny. The incident adds to a string of 2025 exchange security breaches and puts pressure on Mercado Bitcoin to clarify the scope of the compromise. Watch for whether withdrawals resume, confirmation of the affected assets and chains, and any incident postmortem detailing the exploit vector.