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.
Seigniorage
The Swiss 1,000-franc note, worth slightly more than $1,000, is probably the only other banknote in circulation outside its home country. However, it does not have a significant advantage over the €500 note to the non-Swiss; there are 20 times as many €500 notes in circulation, and they are more widely recognized. As a reserve currency, it makes up about 0.1% of the currency composition of official foreign-exchange reserves.