Mercado Bitcoin Says $38M Hit, $11.2M in Assets Frozen

Mercado Bitcoin, one of Brazil’s largest cryptocurrency exchanges, has suspended operations following a security breach involving approximately $38 million in digital assets, with $11.2 million already frozen as investigators trace suspicious transfers across multiple blockchains.

The incident occurred on November 2, when attackers allegedly gained control of wallets associated with the exchange and transferred substantial cryptocurrency holdings to newly created addresses. Mercado Bitcoin initially suspended deposits and withdrawals before temporarily taking its platform offline.

The company maintained that customer assets remained protected and no personal information had been compromised, although independent blockchain researchers continued identifying suspicious transactions after the exchange announced that the incident had been contained.

Mercado Bitcoin Hack Spreads Across 10 Blockchains

The attack involved wallets operating across at least 10 networks, including Bitcoin, Ethereum, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Chain and Stellar.

Blockchain security firm Hypernative initially identified more than $40 million in suspicious transfers, with the largest movements occurring within approximately 34 minutes between 06:19 and 06:53 UTC.

The transferred assets included roughly 106 BTC, 2,852 ETH, 10,700 SOL, 6.7 million XLM and 77,000 AVAX, alongside more than 200 other cryptocurrencies.

The transactions appeared to involve ordinary wallet transfers rather than a smart contract exploit, raising questions about how the attackers obtained authorization to move assets.

Further analysis of the affected wallets estimated total outflows at $48.5 million and identified thousands of Ethereum deposit addresses being emptied after Mercado Bitcoin’s initial containment announcement.

The findings suggest that the compromise may have extended beyond the exchange’s primary hot wallets into infrastructure controlling individual customer deposit addresses. However, the precise attack method and total financial impact remain under investigation.

Mercado Bitcoin subsequently placed the assets involved at approximately $38 million, while reporting progress in blocking funds associated with the incident.

Tether and Other Issuers Help Freeze $11.2 Million

The exchange has coordinated with stablecoin issuers and blockchain intelligence companies to prevent further movement of affected cryptocurrency.

Tether CEO Paolo Ardoino confirmed that more than 4.5 million USDT linked to the incident had been frozen. Mercado Bitcoin later reported approximately $11.2 million in blocked assets through cooperation with partners including Tether, Circle, Paxos, BRL1 and Chainalysis.

Additional funds have been identified as potentially recoverable, although freezing cryptocurrency does not automatically return it to the exchange.

Mercado Bitcoin has notified Brazilian authorities and is continuing forensic investigations while preparing to restore normal services. The company has not announced a confirmed reopening timetable.

The breach comes days after the record $6.3 billion Binance hack, which the FBI attributed to North Korea’s TraderTraitor operation. Binance subsequently resumed withdrawals after replenishing most affected customer assets.

The broader security concerns have extended beyond centralized exchanges. On October 29, Polymarket suffered a $2.7 million wallet-draining attack involving a compromised third-party monitoring service.

No evidence currently connects the Mercado Bitcoin incident to either attack, and the identity of its perpetrators remains unknown.

Mercado Bitcoin has reiterated that customers will not bear losses resulting from the breach. It also warned users against fraudulent reimbursement messages, emphasizing that legitimate support representatives will never request passwords, verification codes or wallet recovery phrases.

The exchange’s immediate priorities remain recovering the affected assets, identifying the security failure and restoring operations without exposing customer funds to further risk.

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