The SARB uses a surplus system to implement monetary policy.

In South Africa, as in many other economies, monetary policy is made by setting a short term-interest rate. Between 1998 and 2022, this rate, known as the repo rate, established the cost for banks of borrowing reserves from the SARB, for one-week periods. In 2022, the SARB reformed its framework for implementing monetary policy. The key policy rate then became the rate banks earn for depositing qualifying funds at the SARB, overnight. This is known as a tiered-floor system. Detailed information on this framework is available here.