Onchain investigator ZachXBT has identified French banking group Crédit Mutuel Arkéa as the alleged victim of a crypto theft exceeding $133 million, warning that total losses could be higher. On Wednesday, the pseudonymous crypto sleuth said the institution, which he described as having $235 billion in assets, was allegedly exploited over multiple days. He also suggested that additional losses may have occurred through over-the-counter (OTC) transactions that were not included in earlier estimates. “I suspect the amount stolen is larger when accounting for OTC activity,” ZachXBT said.The bank’s alleged involvement has not been independently verified, and ZachXBT has not disclosed how the attackers gained access to the funds. Cointelegraph contacted Crédit Mutuel Arkéa for comment but had not received a response by publication.The disclosure follows ZachXBT’s initial report on Monday, when he identified over $106 million in suspicious withdrawals from centralized exchanges. On Tuesday, he raised the estimated losses to over $133 million after discovering another $27 million in withdrawals, some of which occurred after his initial warning.Blockchain analytics firm Bitquery previously traced withdrawals from accounts at Kraken, Crypto.com and OKX. It found that approximately $63 million in stablecoins had been converted into Ether (ETH) within four hours.Kraken and Crypto.com subsequently told Cointelegraph they had restricted accounts or blocked funds associated with the suspected theft. Both exchanges said their platforms remained secure.Related: North Korea denies role in $6.3B Binance hack, points finger at US