Mercado Bitcoin Suspends Deposits and Withdrawals After $40M Multi-Chain Drain

• Mercado Bitcoin suspended deposits and withdrawals after wallets across at least 10 blockchains were drained, with researchers estimating losses above $40 million.
• The transfers used ordinary blockchain transactions rather than a smart contract exploit, while investigators have not established how the attacker obtained signing access.
• Tether froze $4.5 million in linked $USDT. Mercado Bitcoin says customers were not harmed, and no evidence connects the incident to the recent Binance breach.

Mercado Bitcoin suspended deposits and withdrawals after a security incident drained wallets across at least 10 blockchains, with researchers estimating losses above $40 million. An onchain report shared by Pablo Sabbatella tracked outflows between 06:19 and 06:53 UTC. The Brazilian exchange said it contained the incident, customers were not harmed and no data was breached. The episode again puts exchange custody and loss-absorption architecture under scrutiny as investigators trace assets across multiple networks.

Mercado Bitcoin had been hacked for more than USD 40M. pic.twitter.com/4wMBG8vayD

— Pablo Sabbatella @ Devcon 8 🇮🇳 (@PabloSabbatella) November 2, 2026

Multi-Chain Transfers Point to Signing Access Rather Than a Smart Contract Exploit

The reported drain involved plain blockchain transfers rather than exploitation of a smart contract vulnerability. Wallets on Ethereum, Solana, Tron, Polygon, Arbitrum, Avalanche, BNB Chain, Stellar and additional networks sent assets to new addresses. Researchers said the attacker ended up holding roughly 2,852 ETH, 106 BTC, 10,700 SOL, 6.7 million XLM and 77,000 AVAX, alongside more than 200 other tokens. How the attacker obtained authorization to sign those transactions remains unknown.

Mercado Bitcoin paused both deposits and withdrawals as a precaution while teams investigate, track the transferred assets and coordinate with authorities. The company later published destination addresses covering EVM networks, Bitcoin, Solana, Stellar and Tron so counterparties and investigators could monitor movements. The response places operational continuity and asset tracing at the center of the incident, similar to previous multi-chain exchange thefts involving Ethereum and Tron.

Some containment has already occurred. Tether froze $4.5 million in $USDT linked to the incident, showing how issuer-controlled tokens can be restricted after suspicious transfers even when other assets remain movable. Mercado Bitcoin has not publicly disclosed a loss figure, reimbursement requirement or timetable for restoring deposits and withdrawals. The incident arrives months after Tether invested $20 million in Mercado Bitcoin to support its expansion across Latin American onchain finance.

Crucially, no attacker attribution has been announced and there is no public evidence connecting this incident to the recent Binance breach. The timing alone does not establish a shared actor, method or infrastructure compromise. The available evidence instead shows coordinated transfers across many chains using valid transaction paths, leaving signing access as the central unresolved question. A comparable Bitget multi-chain wallet drain previously showed how exchange incidents can spread across several assets without implying a blockchain-level failure. Mercado Bitcoin’s next technical update will determine whether the breach originated in wallet infrastructure, internal authorization systems or another access layer.