Chainalysis Puts Mercado Bitcoin Hack at $49 Million Across 17 Chains

Chainalysis says the Nov. 2 breach at Brazilian crypto exchange Mercado Bitcoin drained about $49 million across 17 blockchains and that a coordinated response helped freeze nearly $10 million in stolen assets.

In its response report, the blockchain investigations firm said the exchange alerted it early in the incident. The largest tranches of stolen assets came from Bitcoin and Ethereum.

Mercado Bitcoin has also issued its own figures: about $38 million in “assets involved” and $11 million blocked through work with partners including Tether, Circle, Paxos, BRL1 and Chainalysis. It did not specify whether the $38 million figure included the blocked assets.

The exchange reiterated that customers “will not suffer any loss of assets” because of the incident, translated from Portuguese. Access to services remains temporarily suspended.

The new accounts follow earlier intraday estimates. The Defiant reported researcher Specter’s $6.8 million freeze tally and Arkham’s $46 million valuation of crypto attributed to the attacker. Arkham’s figure described wallet holdings, rather than an exchange-confirmed loss. The freeze tallies overlap and should not be added together.

From the Alert to Issuer Freezes

Chainalysis said a Mercado Bitcoin director called its local specialist at 2:30 a.m. ET and shared a list of unauthorized transactions. Investigators contacted law enforcement within 30 minutes to relay addresses where assets could be frozen.

The firm said it prioritized centrally issued stablecoins before attackers could swap them into harder-to-disrupt bitcoin or ether. It attributed more than $9 million in freezes to Tether after tracing stolen $USDT. Earlier, Tether CEO Paolo Ardoino had said the issuer froze more than 4.5 million $USDT linked to the incident.

Onchain records show $USDT blacklist actions on Ethereum and Tron against destinations disclosed by Mercado Bitcoin. A USDC blacklist on Polygon also targeted its disclosed Ethereum-compatible address.

A freeze is not a repayment: $USDT’s Ethereum contract blocks outgoing transfers from blacklisted wallets without itself returning the funds to Mercado Bitcoin.

Chainalysis said it was continuing to trace the remaining funds. Mercado Bitcoin said in a subsequent reply that it had no exact reopening timetable and would resume services once full security conditions were met.