Mercado Bitcoin lost around $49 million in a hack on November 2.
Chainalysis says it helped freeze close to $10 million of the stolen funds after contacting law enforcement and several crypto companies.
The attack followed another major crypto theft just days earlier. Binance suffered a breach on October 29, with losses estimated at roughly $6.3 billion. The two incidents differ greatly in scale, but both involved stolen assets moving across several blockchain networks.
In the Mercado Bitcoin case, the funds were spread across 17 blockchains. Bitcoin and Ethereum saw the largest transfers. Transactions also appeared on Base, Tron, Polygon and other networks.
The exchange contacted Chainalysis soon after discovering the breach. At around 2:30 a.m. Eastern Time, one of its directors called the firm’s local representative and provided a list of unauthorized transactions. Chainalysis brought in team members from three continents to follow the money and identify assets that might still be frozen.
That was not possible for every asset. Stablecoins offered one opportunity: their issuers can block funds held at specific addresses. But they need to receive the relevant information before the assets move beyond their reach.
Chainalysis contacted law enforcement within 30 minutes of the initial call and shared addresses where funds could potentially be frozen. It also reached out to stablecoin issuers. By morning, around $4 million in stablecoins had been blocked. More funds were frozen as the response continued.
Several companies took part in the effort, including Paxos, Anchorage Digital, Ripple, Circle and Tether. Chainalysis traced stolen USDT to addresses that could be frozen and passed the findings to Tether and law enforcement. Tether then froze more than $9 million, according to Chainalysis.
The company has not finished tracking the stolen assets. It is still monitoring their movement, flagging addresses linked to the attack and sharing information with other firms.
Nearly $10 million frozen is a small part of the reported $49 million loss. The remaining funds may be harder to recover, particularly if they continue moving between networks. For now, the investigation is focused on tracking those assets and identifying any further opportunities to stop them.
