The monetary setup of the European Central Bank (ECB) centers around short-term securities repurchase agreements (repos) which ensure the flexibility of its money market management. However, a flexible repo-based monetary policy exposes banks to both interest rate risk and liquidity risk. This paper investigates the consequences for the money supply process and the conduct of monetary policy. We develop a loan supply model with maturity transformation and show how banks respond when future monetary policy is expected to become tighter or more uncertain. Our results also shed light on the rationale behind the use of different pricing rules in the ECB's repo auctions.