26 CFR §1.1374-8

1. (a)In general. If any S corporation acquires any asset in a transaction in which the S corporation's basis in the asset is determined (in whole or in part) by reference to a C corporation's basis in the assets (or any other property) (a section 1374(d)(8) transaction), section 1374 applies to the net recognized built-in gain attributable to the assets acquired in any section 1374(d)(8) transaction.
2. (b)Effective date of section 1374(d)(8). Section 1374(d)(8) applies to any section 1374(d)(8) transaction, as defined in paragraph (a)(1) of this section, that occurs on or after December 27, 1994, without regard to the date of the corporation's election to be an S corporation under section 1362.
3. (c)Separate determination of tax. For purposes of the tax imposed under section 1374(d)(8), a separate determination of tax is made with respect to the assets the S corporation acquires in one section 1374(d)(8) transaction from the assets the S corporation acquires in another section 1374(d)(8) transaction and from the assets the corporation held when it became an S corporation. Thus, an S corporation's section 1374 attributes when it became an S corporation may only be used to reduce the section 1374 tax imposed on dispositions of assets the S corporation held at that time. Similarly, an S corporation's section 1374 attributes acquired in a section 1374(d)(8) transaction may only be used to reduce a section 1374 tax imposed on dispositions of assets the S corporation acquired in the same transaction. If an S corporation makes QSub elections under section 1361(b)(3) for a tiered group of subsidiaries effective on the same day, see § 1.1361-4(b)(2).
4. (d)Taxable income limitation. For purposes of paragraph (a) of this section, an S corporation's taxable income limitation under § 1.1374-2(a)(2) for any taxable year is allocated between or among each of the S corporation's separate determinations of net recognized built-in gain for that year (determined without regard to the taxable income limitation) based on the ratio of each of those determinations to the sum of all of those determinations.
5. (e)Examples. The rules of this section are illustrated by the following examples.