History of Switzerland
Switzerland's most important exports during the war were precision machine tools, watches, jewel bearings (used in bombsights), electricity, and dairy products. During World War Two, the Swiss franc was the only remaining major freely convertible currency in the world, and both the Allies and the Germans sold large amounts of gold to the Swiss National Bank. Between 1940 and 1945, the German Reichsbank sold 1.3 billion francs worth of gold to Swiss Banks in exchange for Swiss francs and other foreign currency.
Hard currency
The Swiss franc (CHF) has long been considered a hard currency, and in fact was the last paper currency in the world to terminate its convertibility to gold. In the summer of 2011, the European sovereign debt crisis led to rapid flows out of the euro and into the franc by those seeking hard currency, causing the latter to appreciate rapidly. On September 6, 2011, the Swiss National Bank announced that it would buy an "unlimited" number of euros to fix an exchange rate at 1.00 EUR = 1.20 CHF, to protect its trade. This action temporarily eliminated the franc's hard currency advantage over the euro but was abandoned in January 2015.