Brazil's largest crypto exchange, Mercado Bitcoin, halts deposits and withdrawals after tens of millions of dollars leave the platform
November 2, 2026 (Overnight into November 2, 2026)
Mercado Bitcoin, which calls itself the largest digital assets investment platform in Latin America with about 4.5 million customers, suspended all deposits and withdrawals on Monday, November 2 after a cybersecurity incident. Blockchain security firms said funds began leaving the platform late on Sunday night and reported more than $46 million moved out, a figure the company has not confirmed. Arkham Intelligence identified about $46 million held in wallets it ties to the attacker. Tether froze more than $4.5 million in USDT, and an on-chain analyst counts more than $9 million frozen across nine tokens. The company says the attack did not harm customers or expose personal data, but several blockchain security experts dispute the first claim and point to on-chain evidence that some customer wallets were drained. It published the attacker's destination addresses on Bitcoin, Ethereum-compatible networks, Solana, Stellar and Tron, says Chainalysis is helping track the funds, and says it will restore the platform in the coming days. No one has been blamed, and investigators have not linked the case to the North Korea-linked TraderTraitor group that the FBI blamed for the Binance theft. How the attackers got in has not been disclosed.
Why it matters
It is the second large exchange hit within days of the Binance theft. The company's statement that customers lost nothing is contested by outside analysts, and the total loss and the entry point are still unknown.
What defenders can take from it
- Exchanges: put limits and circuit breakers on hot-wallet withdrawals, and agree in advance how to reach stablecoin issuers and analytics firms so funds can be frozen within minutes.
- Publish attacker addresses early, as Mercado Bitcoin did, so other platforms can block them.
- Customers: keep only what you need to trade on an exchange, rely on the exchange's official channels, and ignore messages that offer compensation or recovery in return for a login or seed phrase.