Like most other central banks in developed countries, the SNB has been remunerating the deposits of banks – their reserves – since the Global Financial Crisis. For many years, the interest rate was negative, so banks were paying the SNB for holding their reserves. As the interest rate has become positive, like other central banks, the SNB is now paying banks. Many reasons explain this general evolution and different central banks have adopted different procedures. While the costs of remunerating reserves are modest elsewhere, they are significant for the SNB because of the unique size of the bank reserves. They are of the same order of magnitude as the maximum profit transfers to the cantons and the Confederation. This report provides a detailed explanation of the new regime and identifies a number of questions that the SNB ought to explain, if only because it has many options to consider for the near and longer term.