The result marked a sharp turnaround from a year ago, when the bank lost 19.2 billion francs as the strong Swiss franc pared down the central bank's foreign currency holdings.
But the Swiss National Bank moved to impose a floor on the franc against the euro on September 6th, 2011, thereby halting the franc's strengthening trend and stabilising the value of its reserves.
The mininum exchange rate of 1.20 franc against the euro had helped to shed the Swiss currency's haven status, thereby also bringing it down against other major currencies such as the dollar and the yen.
As a result, its foreign currency positions contributed 7.7 billion francs to the overall full-year profit while gold holdings made up another 5.4 billion francs.
Gold prices had soared to 47,473 francs per kilogramme at the end of December 2011 from 42,289 francs per kilogram a year ago.