(a) General.

(1) Article III of the convention adopts the principle that an enterprise of one of the contracting States shall not be taxable by the other contracting State upon its industrial and commercial profits unless it is engaged in trade or business in the latter State through a permanent establishment situated therein. Accordingly, a Swiss enterprise is subject to United States tax upon its industrial and commercial profits, to the extent of such profits from sources within the United States, only if it is engaged in trade or business in the United States at some time during the taxable year through a permanent establishment situated therein.

(2) From the standpoint of the United States tax the article has application only to a Swiss enterprise and its industrial and commercial profits from sources within the United States. Thus, a nonresident alien individual who is a citizen of Switzerland, or a Swiss corporation or other entity, carrying on an enterprise which is not Swiss, is subject to tax on such income of such enterprise pursuant to section 871(c) or section 882(a), Internal Revenue Code of 1954, if such alien, corporation, or other entity has engaged in trade or business in the United States at any time during the taxable year, even though it has not had a permanent establishment therein at any time within such year.

(b) No United States permanent establishment. A Swiss enterprise is not subject to United States tax upon its industrial and commercial profits from sources within the United States, nor shall such profits be included in gross income, if it has not at any time during the taxable year engaged in trade or business in the United States through a permanent establishment situated therein. For example, if during the taxable year an enterprise carried on in Switzerland by a nonresident alien individual who is a resident of Switzerland, or by a Swiss corporation, were to sell merchandise, such as watches, dairy products, or liqueurs, in the United States through a commission agent or broker in the United States acting in the ordinary course of his business as such agent or broker, the profits arising from such sale would not be included in gross income and would be exempt from United States tax under Article III of the convention. Similarly, if during the taxable year such enterprise were to secure orders in the United States for such merchandise through its sales agents whose sole function in the United States is sales promotion, the orders being transmitted to Switzerland for acceptance, then the profits arising from such sales would not be included in gross income and would be exempt from United States tax.

(c) United States permanent establishment—(1) General. A Swiss enterprise is subject to United States tax upon its industrial and commercial profits from sources within the United States to the same extent as are nonresident aliens or foreign corporations which are subject to tax pursuant to section 871(c) or section 882(a), Internal Revenue Code of 1954, if such enterprise has at any time during the taxable year engaged in trade or business in the United States through a permanent establishment situated therein. If it is so engaged, it is subject to United States tax upon its entire income from sources within the United States except to the extent otherwise exempt from United States tax.

(2) Allocation of profits. In the determination of the income taxable to such enterprise for purposes of the United States tax, all industrial and commercial profits from sources within the United States shall be deemed to be allocable to the permanent establishment in the United States. Hence, if a Swiss enterprise which has a permanent establishment in the United States at some time during the taxable year were to sell in the United States, through a commission agent therein acting in the ordinary course of his business as such, merchandise which has been produced in Switzerland, the profits arising from such sale would be allocable to the permanent establishment to the extent they are derived from sources within the United States, even though the sale is made independently of the permanent establishment.

(3) Independent basis. The industrial and commercial profits of the permanent establishment in the United States shall be determined as if the establishment were an independent enterprise engaged in the same or similar activities under the same or similar conditions and dealing at arm's length, or on an independent basis, with the enterprise of which it is a permanent establishment.