On-Chain Trail Links BitMart Breach to Mercado Bitcoin Attack

On-chain transfers from wallets linked to BitMart’s Nov. 2 breach reached an address also involved in the Mercado Bitcoin attack; neither exchange has confirmed that a single attacker controlled both sets of wallets.

About $424,000 was taken from wallets linked to BitMart across Base, Arbitrum, Optimism and five smaller blockchains. The initial outflows on the first three networks were valued at roughly $298,000, so the figures cover different scopes.

BitMart founder Sheldon Xia said the exchange was hacked Nov. 2 but called the amount small. “We acted quickly to investigate and strengthen security,” Xia said.

About $48.6 million left Mercado Bitcoin wallets across 11 blockchains on Nov. 2. The Brazilian exchange said about $11 million had been blocked and about $38 million remained unblocked, while saying customers would not lose assets.

Mercado Bitcoin said the breach affected hot wallets and that it paused deposits and withdrawals. The wallet links rely on address labels and on-chain behavior; neither exchange confirmed that the same attacker controlled the wallets.