Mercado Bitcoin, the leading Brazilian cryptocurrency exchange, has suspended customer withdrawals after approximately $40 million in digital assets were drained across 10 blockchain networks, according to a report by BitcoinKE.

The exchange halted withdrawals while it investigates the breach, which involved stolen assets moving across multiple networks. The multi-chain movement highlights the difficulty of containing security incidents in an interconnected crypto ecosystem, where funds can be routed between chains faster than affected platforms can respond.

According to the report, the attacker currently holds roughly:

• 2,852 ETH
• 106 BTC
• 10,700 SOL
• 6.7 million XLM
• 77,000 AVAX

along with more than 200 additional tokens.

Paolo Ardoino, chief executive of stablecoin issuer Tether, confirmed that more than 4.5 million USDT linked to the hack has been frozen. That action locks the linked tokens on the issuer's network so they cannot be moved further, while the remainder of the stolen assets remain in the attacker's possession.

The incident comes amid heightened scrutiny of cryptocurrency security, following a separate $6.3 billion breach at Binance that the FBI has attributed to North Korean-linked hackers. As that case demonstrated, cross-chain transactions can complicate efforts to trace and recover stolen assets, particularly when attackers move funds between networks and through decentralized exchanges. Even when every transaction remains publicly visible on-chain, movement across chains and venues can make the trail harder to follow in practice.

Mercado Bitcoin has not yet provided a full account of the incident, including how the attacker gained access, or indicated when withdrawals will resume. The suspension underscores the operational risks facing centralized crypto exchanges, where a security failure can cut off customer access to funds even while the movement of stolen assets remains visible on public blockchains. For now, the key developments to watch are whether additional issuers or platforms freeze linked funds as Tether has done, and when the exchange restores customer access to withdrawals.