Cyberattack on Crédit Mutuel Arkéa: up to $1 billion stolen?

Crédit Mutuel Arkéa has confirmed a cyberattack of potentially unprecedented scale, with roughly $133 million in suspicious on-chain movements identified across blockchains while some sources estimate total losses approaching $1 billion. The discrepancy between the confirmed on-chain transfers and the larger reported figure suggests the full scope of the breach has yet to be established. The incident matters because it marks one of the largest cyber heists linked to a traditional European bank with exposure to crypto rails, raising questions about custody and counterparty risk. What remains unclear is the fraudsters' mode of operation and whether the near-$1 billion estimate reflects stolen assets, frozen funds, or notional exposure. Watch for Arkéa's official loss figure, any asset recovery or tracing efforts, and whether the affected blockchain flows point to a specific protocol or custodian.