26 CFR § 1.1002-1 - Sales or exchanges.
(a) General rule. The general rule with respect to gain or loss realized upon the sale or exchange of property as determined under section 1001 is that the entire amount of such gain or loss is recognized except in cases where specific provisions of subtitle A of the code provide otherwise.
(b) Strict construction of exceptions from general rule. The exceptions from the general rule requiring the recognition of all gains and losses, like other exceptions from a rule of taxation of general and uniform application, are strictly construed and do not extend either beyond the words or the underlying assumptions and purposes of the exception. Nonrecognition is accorded by the Code only if the exchange is one which satisfies both (1) the specific description in the Code of an excepted exchange, and (2) the underlying purpose for which such exchange is excepted from the general rule. The exchange must be germane to, and a necessary incident of, the investment or enterprise in hand. The relationship of the exchange to the venture or enterprise is always material, and the surrounding facts and circumstances must be shown. As elsewhere, the taxpayer claiming the benefit of the exception must show himself within the exception.
(c) Certain exceptions to general rule. Exceptions to the general rule are made, for example, by sections 351(a), 354, 361(a), 371(a)(1), 371(b)(1), 721, 1031, 1035 and 1036. These sections describe certain specific exchanges of property in which at the time of the exchange particular differences exist between the property parted with and the property acquired, but such differences are more formal than substantial. As to these, the Code provides that such differences shall not be deemed controlling, and that gain or loss shall not be recognized at the time of the exchange. The underlying assumption of these exceptions is that the new property is substantially a continuation of the old investment still unliquidated; and, in the case of reorganizations, that the new enterprise, the new corporate structure, and the new property are substantially continuations of the old still unliquidated.