This paper studies the effects of stablecoin adoption—crypto-assets designed to maintain a stable value relative to a reference asset—on bank intermediation and the transmission of monetary policy. Using evidence from the rapid expansion of stablecoins combined with confidential granular data on euro area banks and their individual borrowers, we document three main findings. First, stablecoin adoption induces a deposit-substitution mechanism, whereby funds shift from retail bank deposits to digital assets. This reallocation increase