Legal tender
The Swiss franc is also the currency used for administrative and accounting purposes by most of the numerous international organisations that are headquartered in Switzerland.
Liechtenstein–Switzerland relations
At the request of Liechtenstein's government in 1919, Switzerland safeguards Liechtenstein's interests and citizens abroad. The two form a common economic and monetary area (Liechtenstein has used the Swiss franc (since 1920) and has had a customs union (since 1924) with Switzerland with open borders (though both are now also party to the Schengen Agreement). The countries also have a common patent system. Switzerland is empowered to enter into treaties on Liechtenstein's behalf if Liechtenstein is not represented at the treaty negotiations; this power has most often been exercised with treaties involving customs duties or procedures.