Brazil's Mercado Bitcoin Hit by $40M Hack, $11M Frozen - Bitbo
Brazil's largest crypto exchange, Mercado Bitcoin, was hacked on November 2, draining funds from its hot wallets with about $11 million frozen with help from Tether, Circle and Chainalysis.
The exchange confirmed the attack in a Portuguese-language statement on X, writing: "We identified and quickly contained a security incident in one of our systems early this morning. As a preventive protection measure, deposits and withdrawals are temporarily suspended."
Blockchain security firm Hypernative flagged more than $40 million in suspicious transfers across at least 10 blockchains, including Bitcoin, Ethereum, Solana and Tron. In an evening update, Mercado Bitcoin said it had blocked around $11 million with partners including Tether, Circle, BRL1, Paxos and Chainalysis, while about $38 million remained unfrozen.
Stablecoin issuers step in
Tether CEO Paolo Ardoino confirmed his company's involvement, writing on X: "Tether froze more than 4.5M USDT related to this security incident." Chainalysis reported that a Mercado Bitcoin director contacted its team at 2:30 a.m. Eastern Time, and within 30 minutes it was relaying freezable addresses to law enforcement.
This was not simply a case of tracing assets on the blockchain. It required our investigators to identify an opportunity for intervention, understand which organisations could act, and rapidly coordinate the necessary response.
Questions over the scope
Blockchain data firm Bitquery counted $48.6 million taken across 10 blockchains, noting the hacker emptied 36,042 customer deposit addresses on Ethereum and continued for about four hours after the exchange claimed the attack was contained. Mercado Bitcoin assured no customer data leaked and promised to share a timeline for reopening the platform in upcoming updates.
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