The amount raised by charging interest on sight deposit balances it holds for commercial banks above a certain threshold increased slightly from the 2.02 billion francs the SNB made from the charge during 2017.

The aim is to deter investors buying Swiss francs, and is part of the SNB's campaign to combat the value of the currency, which it regards as "highly-valued" and whose strength hurts Switzerland's export-reliant economy.

The profit from negative rates was however dwarfed by the 16.3 billion loss it made on its foreign currency positions, the result of its market interventions also designed to weaken the franc.

As a result the SNB posted an annual loss of 14.9 billion francs, just below the bank's provisional calculations in January for a 15 billion franc loss..

Still, the bank was able to make a payout to shareholders after making a record profit of 54.4 billion francs in 2017. The SNB proposed a dividend of 15 francs per share, the legal maximum, and a payout of 2 billion francs to the Swiss cantons and the central government.