Enterprise.
(6) Enterprise. The term enterprise means any commercial or industrial enterprise or undertaking carried on by any person, for example, by an individual partnership, or corporation. It includes such activities as manufacturing, merchandising, mining, processing, banking, and insuring. It does not include the rendition of personal services. Hence, a nonresident alien individual who is resident of Switzerland and who performs personal services is not, merely by reason of such services, engaged in a Swiss enterprise within the meaning of the convention; consequently, his liability to United States tax is not determined under Article III of the convention, if he has not otherwise carried on a Swiss enterprise.