26 CFR § 1.280F-4T - Special rules for listed property (temporary).
(a) Limitations on allowable recovery deductions in subsequent taxable years -
(1) Subsequent taxable years affected by reason of personal use in prior years. For purposes of computing the amount of the recovery deduction for “listed property” for a subsequent taxable year, the amount that would have been allowable as a recovery deduction during an earlier taxable year if all of the use of the property was use described in section 168(c) is treated as the amount of the recovery deduction allowable during that earlier taxable year. The preceding sentence applies with respect to all earlier taxable years, beginning with the first taxable year in which some or all use of the “listed property” is use described in section 168(c). For example, on July 1, 1984, B purchases and places in service listed property (other than a passenger automobile) which is 5-year recovery property under section 168. B selects the use of the accelerated percentages under section 168. B's business/investment use of the property (all of which is qualified business use as defined in section 280F(d)(6)(B) and § 1.280F-6(d)(2)) in 1984 through 1988 is 80 percent, 70 percent, 60 percent, and 55 percent, respectively, and B claims recovery deductions for those years based on those percentages. B's qualified business use for the property for 1989 and taxable years thereafter increases to 100 percent. Pursuant to this rule, B may not claim a recovery deduction in 1989 (or for any subsequent taxable year) for the increase in business use because there is no adjusted basis remaining to be recovered for cost recovery purposes after 1988.
(2) Special rule for passenger automobiles. In the case of a passenger automobile that is subject to the limitations of § 1.280F-2T, the amount treated as the amount that would have been allowable as a recovery deduction if all of the use of the automobile was use described in section 168(c) shall not exceed $4,000 for the year the passenger automobile is placed in service and $6,000 for each succeeding taxable year (adjusted to account for the automobile price inflation adjustment, if any, under section 280F(d)(7) and for short taxable year under § 1.280F-2T(i)(2)). See. § 1.280F-3T(g). Example 8.
(b) Treatment of improvements that qualify as capital expenditures -
(1) In general. In the case of any improvement that qualifies as a capital expenditure under section 263 made to any listed property other than a passenger automobile, the rules of this paragraph (b) apply. See § 1.280F-2T(f) for the treatment of an improvement made to a passenger automobile.
(2) Investment tax credit allowed for the improvement. If the improvement qualifies as an investment in new section 38 property under section 48(b) and § 1.48-2(b), the investment tax credit for that improvement is limited by paragraph (b)(1) of § 1.280F-3T, as applied to the item of listed property as a whole.
(3) Cost recovery of the improvement. The improvement is treated as a new item of recovery property. The method of cost recovery with respect to that improvement is limited by § 1.280F-3T(c), as applied to the item of listed property as a whole.