Mercado Bitcoin, Brazil's Top Exchange, Hacked for $40-46 Million

Mercado Bitcoin, Brazil's largest cryptocurrency exchange, suspended deposit and withdrawal services in the early hours of Monday, November 2, 2026, after detecting a security incident in one of its systems. The exchange said no customer funds were lost and no personal data leaked as a result.

Blockchain security firm Hypernative was the first to sound the alarm publicly, tracking more than $40 million in suspicious transfers moving across at least 10 different blockchains within a short window. Mercado Bitcoin has not officially confirmed that figure in its own statements.

Hypernative is known for monitoring on-chain activity in real time to flag suspicious transaction patterns, including theft from exchanges or crypto protocols. This kind of detection often surfaces faster than an official statement from the affected company, since security firms can observe fund movements directly on-chain without waiting for internal confirmation.

Hours after Hypernative's report, The Block reported a higher number, $46 million, as the confirmed value of the security breach. The gap between $40 million and $46 million likely reflects an investigation still in progress, with the traced amount growing as security teams follow asset movements across multiple chains.

Timeline of the Incident

According to Decrypt, Mercado Bitcoin identified the problem in the early hours of Monday local time. Once detected, the exchange immediately halted all deposit and withdrawal activity, a standard industry practice during a suspected breach meant to limit how much an attacker can cash out from a compromised system.

The crypto industry generally distinguishes between smart contract exploits, hot wallet compromises, and breaches within a company's internal systems. Mercado Bitcoin described the incident as affecting one of its systems but has not specified whether it involved a hot wallet, an internal API, or another piece of infrastructure. Technical details like these usually only emerge once a forensic investigation wraps up.

In its statement, Mercado Bitcoin stressed two points: no customer funds were lost, and no personal user data leaked. That distinction matters because it determines whether the losses hit the exchange's internal treasury or actually touched individual user balances. So far, the exchange is framing the incident as a problem on its own systems rather than customer accounts.

Tether Freezes Funds Tied to the Incident

Tether CEO Paolo Ardoino confirmed the company froze more than 4.5 million USDT identified as linked to the stolen funds. Technically, stablecoin issuers like Tether can freeze specific wallet addresses through a blacklist function built into the USDT smart contract, preventing tokens at that address from moving any further.

This kind of freeze has become a recurring pattern in major crypto hack cases. USDT is often one of the assets attackers use to cash out stolen funds before converting them into other assets or withdrawing to fiat. Still, 4.5 million USDT is only a small fraction of the estimated $40 million to $46 million total loss, suggesting most of the funds had likely already moved into other assets or spread across multiple blockchains before Tether could act.

Mercado Bitcoin's Standing in Brazil's Crypto Market

Mercado Bitcoin is known as Brazil's largest crypto exchange, operating in one of Latin America's biggest crypto markets. That status gives this incident more weight than a breach at a smaller platform would carry, given its broad user base and role as a key gateway for Brazilians entering digital assets.

Suspending deposits and withdrawals at an exchange this size directly affects daily liquidity for local users. Many Mercado Bitcoin customers rely on the platform to convert between the Brazilian real and various crypto assets, so the service halt could disrupt everyday transactions for as long as the investigation continues.

Suspicious Funds Spread Across 10 Blockchains

Hypernative's finding that funds moved across at least 10 different blockchains points to an attack pattern that's fairly difficult to trace. Spreading funds across many networks at once is typically a strategy to complicate tracking and slow down freezing efforts by authorities or stablecoin issuers like Tether, since each blockchain has its own transaction confirmation mechanics and speed.

As of this writing, Mercado Bitcoin has not released official details on which blockchains were involved, the attack method used, or whether any party has been identified as responsible. The investigation is reportedly still ongoing, and further details will likely only be announced once the security team finishes tracing activity across all the networks involved.

What It Means for Traders

For Mercado Bitcoin users, the first thing to watch is an official announcement on when deposit and withdrawal services will fully resume. As of this writing, the exchange has not given a firm timeline for restoring service.

Traders holding assets on Mercado Bitcoin should keep an eye on the exchange's official channels for investigation updates, including any further compensation measures or a published security audit once the incident is fully resolved. The gap between Hypernative's $40 million figure and The Block's confirmed $46 million is also worth tracking, since it could signal the final loss total will be revised further.

Beyond this specific case, the incident is a reminder of the risks tied to holding large amounts of assets on centralized exchanges rather than moving them to self-custody wallets with full control over private keys. Tether's freezing pattern is also worth watching as an indicator of how quickly stablecoin issuers can respond to theft cases, and how much of the stolen funds can realistically be recovered through this kind of freeze.