Tether says it froze more than 4.5 million USDT linked to a security incident at Brazilian exchange Mercado Bitcoin. Separately, Brazilian outlet BitNotícias reported more than $40 million in suspicious transfers from wallets attributed to the exchange. Neither figure establishes the final loss or how much may be recovered.
- Tether CEO Paolo Ardoino announced the freeze.
- BitNotícias attributed its larger transfer estimate to a Hypernative alert.
- Mercado Bitcoin paused deposits and withdrawals during its investigation.
- The exchange said customers were unharmed and no data breach occurred.
What happened at Mercado Bitcoin?
Mercado Bitcoin said it identified and quickly contained a security incident affecting one of its systems early on Nov. 2. The statement did not specify the year or explain how the incident occurred.
The exchange temporarily suspended deposits and withdrawals as a precaution while it investigated and tracked assets. In a later update, it said it was working to restore operations safely. The available updates do not say whether transfers have resumed.
Mercado Bitcoin said customers suffered no harm and no data breach occurred. These are the exchange’s claims, and the information available does not independently verify them. The company also said it was coordinating measures with relevant authorities, without naming them.
What the $4.5 million freeze means, and what it doesn’t
Tether CEO Paolo Ardoino announced the freeze, saying:
“Tether froze more than 4.5M USDT related to this security incident, ”
USDT is the dollar-linked stablecoin issued by Tether. Ardoino described the frozen tokens as related to the incident, but the announcement does not say they were returned to Mercado Bitcoin. Tether has also frozen USDT in a separate Brazil tax dispute and gambling probe.
The freeze is separate from the larger figure reported by BitNotícias. The outlet said security company Hypernative flagged more than $40 million in suspicious transfers from wallets attributed to Mercado Bitcoin. The transfers went to newly created destination addresses across at least 10 blockchain networks.
That figure refers to reported transfers, not confirmed losses. The report did not explain how it was calculated or whether repeated movements could have been counted more than once. It also does not establish how much was frozen or recovered. Tether’s figure, by contrast, specifically refers to USDT that the company said it blocked.
A freeze can stop particular USDT from moving on networks where Tether supports that control. Centralized stablecoin issuers can use this tool to respond to suspected illicit activity, but it also gives Tether power over those tokens. Tether’s governance has also drawn attention after it added an independent director and restored an audit committee. Bitcoin has no issuer with the same ability to freeze coins.
Addresses published to help track funds
Mercado Bitcoin published destination addresses under five labels: EVM-compatible networks, Bitcoin, Solana, Stellar and Tron. EVM-compatible networks share compatibility with the Ethereum Virtual Machine, so that category can cover multiple networks. The exchange said it disclosed the addresses solely to help identify and track assets.
The published EVM-compatible address was 0xe485e7A70b1131216Cb47CA4555c4Bbb2C742478. Mercado Bitcoin did not provide a value breakdown by address or network, or say how much remained at any destination.
The exchange’s “Bitcoin” label identifies one of its address categories, but the available details do not specify the protocol or layer involved. It does not mean the address held USDT on Bitcoin.
Published addresses give investigators and observers a reference for monitoring transactions. On their own, they do not prove who controls an address or show that funds can be seized or returned. Blockchain visibility is useful, but it is not a recovery plan.
Was Brazil’s crypto monitoring system involved?
An earlier report in August said Brazil’s central bank and Hypernative had developed a real-time crypto threat-monitoring and alert-sharing system. Mercado Bitcoin and Foxbit were named as planned integration participants. Testing was complete, and participants were preparing their systems to receive and redistribute alerts.
Mercado Bitcoin has not said whether the system was used in this incident. Its existence shows that efforts are underway to share warnings about suspicious transfers, but it does not show that the system detected or helped contain this event.
Key questions and answers
-
How much USDT did Tether freeze?
More than 4.5 million USDT, according to CEO Paolo Ardoino.
-
Were the frozen tokens returned to Mercado Bitcoin?
No return has been reported. A freeze blocks movement, but does not by itself establish that funds were recovered.
-
What does the reported $40 million represent?
BitNotícias reported that Hypernative flagged more than $40 million in suspicious transfers from wallets attributed to Mercado Bitcoin. The report did not explain how the figure was calculated or establish it as a confirmed loss.
-
What happened to customers and their data?
Mercado Bitcoin said customers suffered no harm and there had been no data breach. The exchange provided no further technical details about the incident.
-
Have deposits and withdrawals resumed?
The available updates do not confirm that they have resumed. Mercado Bitcoin said it was working to restore operations safely.
-
How much could ultimately be recovered?
No final recoverable total has been established. The frozen USDT and published addresses are measures to contain and track funds, not confirmation that they have been returned.
