26 CFR 509.110: Patent and copyright royalties and film rentals.

Royalties and other amounts representing consideration for the right to use copyrights, artistic and scientific works, patents, designs, plans, secret processes and formulae, trademarks, and other like property and rights, including rentals and like payments in respect to motion picture films or for the use of industrial, commercial, or scientific equipment, which are derived from sources within the United States by a nonresident alien individual who is a resident of Switzerland, or by a Swiss corporation or other entity, are exempt from United States tax under the provisions of Article VIII of the convention if such alien, corporation, or other entity at no time during the taxable year in which such items of income are derived has a permanent establishment in the United States.