What exactly happened?
Mercado Bitcoin, according to The Block the largest cryptocurrency exchange in Brazil, confirmed a security incident and suspended withdrawals. The Block dates the confirmation to Monday and speaks of a breach in the range of roughly $46 million.
Chainalysis, a company that specializes in blockchain analysis, cites a higher figure in its own assessment. According to it, the attack led to a loss of approximately $49 million, and the stolen funds were spread across 17 different blockchains. This strategy (splitting the loot across many networks) typically complicates tracing and freezing.
The difference between $46 million and $49 million does not yet have a clear explanation. The figures come from different sources and at different moments, and the value of the stolen tokens also changes with the market price. Treat this as a range, not a single fixed number.
How much money was successfully blocked?
Here the individual sources complement one another, and it is useful to separate them.
| Entity | Amount blocked | Source |
|---|---|---|
| Chainalysis (freeze coordination) | nearly $10 million | Chainalysis |
| Tether (USDT freeze) | $4.5 million | CryptoSlate |
| Mercado Bitcoin (own tally) | $11 million | The Defiant |
Chainalysis describes leading a coordination effort that resulted in the freezing of nearly $10 million in stolen funds. Tether, the issuer of the USDT stablecoin, froze $4.5 million according to CryptoSlate. Mercado Bitcoin itself, according to The Defiant, states that $11 million was blocked.
These figures partly overlap and partly complement each other. The Tether freeze may be part of the broader coordination led by Chainalysis, and at the same time may not fully align with what the exchange counts in its $11 million. The exact total of uniquely blocked funds cannot be clearly derived from public sources.
How much does the attacker still have available?
According to CryptoSlate, the attacker holds roughly $46 million in cryptocurrencies. That fits the picture in which only a minority of the total damage was frozen and most of the funds remain in addresses under the attacker's control.
Mercado Bitcoin, according to CryptoSlate, published tracking addresses without disclosing a timeline for reopening or the exact financial damage. Recovery work is ongoing, according to the exchange.
Will customers lose money?
Mercado Bitcoin, according to The Defiant, states that no customer will suffer a loss. At the same time, access to its services remains suspended.
This is a promise from the exchange, not a verified fact. Until services are restored and clients have normal access to their funds, this is a claim that can only be verified later based on what actually happens. That is exactly what we will be watching.
What remains unknown?
- How the breach occurred. Public sources do not describe the specific technical attack vector (whether it was a compromise of keys, an internal system, or something else).
- Who is behind the attack. None of the verified sources identifies the attacker.
- When services will be restored. The exchange has not given a date.
- The final damage figure. It ranges from approximately $46 million to $49 million depending on the source and the moment of valuation.
What to watch for in this type of event
In exchange hacks, the picture changes in the first hours and days. It is worth distinguishing three things: the total amount stolen, the amount that was successfully frozen, and what ultimately actually makes its way back. Freezing funds (typically with stablecoins like USDT, which the issuer technically controls) does not automatically mean they will be returned. Spreading the loot across many blockchains, here 17 according to Chainalysis, is usually a sign of an effort to make tracing harder.
charliedesk will follow this event and compare later developments with what the exchange and the involved firms have promised now.