Mercado Bitcoin, Brazil’s largest crypto exchange, says about $38 million was taken from its hot wallets on Monday, and that it will cover all of it. CoinDesk reports that wallets on at least 10 blockchains were emptied.
Arkham’s data puts the assets involved at about $46.3 million, according to The Block, and early researcher estimates cited by CoinDesk were above $40 million. The exchange has not explained the gap between its figure and the others.
Recovery has started. CoinDesk says Tether, Circle and Chainalysis helped freeze about $11 million. The Block quotes Tether chief executive Paolo Ardoino saying Tether froze more than 4.5 million USDT, and neither piece reconciles the two numbers.
Mercado paused deposits and withdrawals, published the destination addresses so others could trace them, and said no customer data leaked. The Block’s figure was published on Monday and CoinDesk’s on Tuesday, so the two may reflect different moments in the investigation. Arkham analyst Emmett Gallic told The Block the attacker was sweeping older deposit addresses and selling memecoins and altcoins.
The theft arrives days after the Binance hack of about $6.3 billion, which has made exchange security a live question for every platform. Both accounts lean heavily on Mercado’s own posts and on Arkham’s tracking.
A promise to cover losses is only as good as the balance sheet behind it. Mercado has not said who is paying, has not identified the attacker, and has not said when customers can withdraw again.
