Mercado Bitcoin Halts Withdrawals, Tether Freezes USDT

The exchange says it identified and contained the incident early Monday and paused user access as a precaution. It maintains that no customers were harmed and that no data breach was detected. Tether CEO Paolo Ardoino confirmed the freeze, and Mercado Bitcoin repeated its no-compromise position in a Portuguese-language statement on X.

The exchange has also published the destination addresses linked to the incident, spread across EVM networks, Bitcoin, Solana, Stellar, and Tron. It says they are for identification and tracking only. Its teams are tracing assets and working with authorities, but there is no timeline for resuming operations.

Arkham Puts the Figure at $46 Million, the Exchange Says Nothing

Blockchain analytics firm Arkham reports that a wallet it labels the “Mercado Bitcoin Hacker” holds about $46 million in crypto, with sizable positions in ETH, BTC, and PEPE. Mercado Bitcoin has not confirmed any loss figure, and it has not called the incident a hack.

This is the second large Tether freeze in about a week. The stablecoin issuer froze over 1.567 billion USDT linked to a separate Binance hack last week, and stablecoin issuers are increasingly acting as a first line of defense when exchanges are drained.

Hashlytics Take

A freeze only works on what the issuer controls. Tether can lock USDT in minutes, but Arkham’s tally leans on ETH, BTC, and PEPE, which no company can freeze. That makes the 4.5 million USDT a partial win at best, and it shows why attackers convert to native assets quickly. The wording matters too: “security incident” with no loss figure and no hack label is how an exchange buys time. If users cannot withdraw for long, the missing numbers will start to matter more than the contained-incident line.