Mercado Bitcoin Goes Dark After $49M Hit, $11.2M Already Frozen

Mercado Bitcoin pulled its entire platform offline after a security incident that put roughly $49 million in crypto assets at risk. The Brazilian exchange says no clients lost money and no data leaked, according to Valor Econômico.

The company says it moved fast. With help from partners including Tether, Circle, BRL1, Paxos and Chainalysis, it blocked $11.2 million of the assets before they could disappear further. In a post on X, the exchange said it had 'identified and swiftly contained a security incident in one of our systems early this morning.'

Outside estimates are messier than the headline number. Blockchain data firm Arkham says the attacker drained about $46.3 million in crypto from the platform. Security firm Hypernative had already flagged around $40 million in outflows from wallets it ties to the exchange.

Tether CEO Paolo Ardoino says the stablecoin issuer froze more than 4.5 million USDT linked to the incident, another chunk of the haul locked down. Mercado Bitcoin published the destination wallet addresses tied to the attack across EVM networks, Bitcoin, Solana, Stellar and Tron so the funds could be tracked.

The exchange paused deposits and withdrawals first, then went fully dark while its teams investigate and coordinate with authorities. It says the platform stays offline until it can safely restart, and that it will post a timeline on its official channels.

Mercado Bitcoin is also warning users about scammers circling the chaos, reminding customers that it never asks for passwords, verification codes or recovery phrases.