Mercado Bitcoin suspends withdrawals after incident

Mercado Bitcoin said it identified and contained a security incident in one of its systems and temporarily suspended deposits and withdrawals while it investigated. The company said the incident did not harm customers or lead to a data leak, while Tether reported freezing more than $4.5 million in USDT linked to the case.

What is known about the incident?

Mercado Bitcoin did not confirm a definitive loss, but it did acknowledge an ongoing incident and said it had halted transfers to review what happened. According to Arkham Intelligence, the wallets it attributes to the attacker held about $46 million in cryptocurrency, although the source itself labeled that figure as an attribution not confirmed by the exchange.

The analytics firm also described a drain from Mercado Bitcoin hot wallets across at least ten blockchains, with the first movement identified on Base at 01:22 UTC. Arkham did not publicly detail which system was compromised, and the method the attacker used to gain transaction authorization was still not publicly determined, according to another report cited in the material.

What measures did the exchange take and how did tracing continue?

Mercado Bitcoin published wallet addresses linked to the incident to help with monitoring and asset tracing. It was also coordinating the investigation with authorities and with companies in the ecosystem to track the movement of funds, according to the information available.

In that context, Arkham said Tether froze more than 4.5 million USDT linked to the incident. Other reports cited different locks and estimates, also not definitively confirmed by the exchange. Yahoo Finance said Mercado Bitcoin had initially estimated about $38 million in assets were involved and that it had blocked nearly $11 million with help from Tether, Circle, Paxos, BRL1 and Chainalysis.

The Crypto Times, meanwhile, said researcher Specter had estimated about $9.17 million in crypto assets frozen across several tokens. Bitcoinist reported suspicious transfers of more than $40 million, while CoinDesk said about $40 million was drained across 10 chains. In every case, the core point remains the same: an open investigation, figures still under review, and an on-chain attribution that does not amount to a final loss confirmed by Mercado Bitcoin.