26 CFR § 1.1374-1 - General rules and definitions.
(b) Anti-trafficking rules. If section 382, 383, or 384 would have applied to limit the use of a corporation's recognized built-in loss or section 1374 attributes at the beginning of the first day of the recognition period if the corporation had remained a C corporation, these sections apply to limit their use in determining the S corporation's pre-limitation amount, taxable income limitation, net unrealized built-in gain limitation, deductions against net recognized built-in gain, and credits against the section 1374 tax.
(c) Section 1374 attributes. Section 1374 attributes are the loss carryforwards allowed under section 1374(b)(2) as a deduction against net recognized built-in gain and the credit and credit carryforwards allowed under section 1374(b)(3) as a credit against the section 1374 tax.
(d) Recognition period. The recognition period is the 10-year (120-month) period beginning on the first day the corporation is an S corporation or the day an S corporation acquires assets in a section 1374(d)(8) transaction. For example, if the first day of the recognition period is July 14, 1996, the last day of the recognition period is July 13, 2006. If the recognition period for certain assets ends during an S corporation's taxable year (for example, because the corporation was on a fiscal year as a C corporation and changed to a calendar year as an S corporation or because an S corporation acquired assets in a section 1374(d)(8) transaction during a taxable year), the S corporation must determine its pre-limitation amount (as defined in § 1.1374-2(a)(1)) for the year as if the corporation's books were closed at the end of the recognition period.
(e) Predecessor corporation. For purposes of section 1374(c)(1), if the basis of an asset of the S corporation is determined (in whole or in part) by reference to the basis of the asset (or any other property) in the hands of another corporation, the other corporation is a predecessor corporation of the S corporation.