Zinskoridors

Zinskoridors, or interest rate corridors, describe a monetary policy framework in which a central bank defines a band within which short‑term interest rates are expected to move. The corridor is formed by two bound rates: the lower bound, usually the rate on the central bank's overnight deposit facility, and the upper bound, the rate on the central bank's lending facility. The policy rate is typically set near the middle of the band.

Operation: If market rates approach the upper bound, the central bank lends to banks at or near that bound to prevent rates from rising further. If rates approach the lower bound, banks can place excess reserves at the central bank or borrow at the lower bound, depending on the design. The corridor thus anchors expectations and provides a predictable ceiling and floor for overnight rates.

Structure and variants: Some corridors are explicit with published bounds; others are implicit, inferred from the design of facilities and market instruments. The width of the corridor varies by country and time and may be widened in periods of stress to ease liquidity.

Examples: The euro area uses an implicit corridor formed by the deposit facility rate and the marginal lending facility rate, with the main refinancing rate near the middle. Several other central banks have operated explicit corridors in the past, especially after financial crises, to strengthen policy transmission.

Impact and considerations: Benefits include improved predictability of policy, improved interbank rate transmission, and a clearer anchor for expectations. Limitations include potential distortions under large liquidity injections and the sensitivity of corridor width to financial conditions.