(A) If as of January 1, 1985, a taxpayer is for federal income tax purposes amortizing a capital expense paid or incurred before January 1, 1985, as provided in Internal Revenue Code Sections 171 (Amortization of Bond Premium), 174 (Research and Experimental Expenditures), 185 (Amortization of Railroad Grading and Tunnel Bores), 189 (Amortization of Real Property Construction Period Interest and Taxes), or 194 (Amortization of Reforestation Expenditures), the taxpayer is allowed to deduct for South Carolina income tax purposes the amount amortized and deducted for federal income tax purposes. At the expiration of the amortization for federal income tax purposes, the taxpayer may continue to amortize, for South Carolina income tax purposes, the balance of the capital expense, if any, using the same rate of amortization until the cost of the item has been fully amortized for South Carolina income tax purposes.

(B) Except as provided in subsection (C), if, as of January 1, 1985, a taxpayer is deducting the cost of personal property placed in service before 1985, or the cost of improvements to real property paid or incurred before January 1, 1985, as provided in Internal Revenue Code Section 168, the taxpayer is allowed for South Carolina income tax purposes the same annual deduction as allowed for federal tax purposes. Beginning with the year following the expiration of the deductions for federal tax purposes, the balance of the deductible cost, if any, may be deducted at the rate of fifty percent a year for personal property and twenty percent a year for real property improvements, until the entire deductible cost has been deducted for South Carolina income tax purposes. The deduction authorized by this subsection may not exceed the taxpayer’s depreciable basis.

(C) If a taxpayer has a higher basis in assets for South Carolina income tax purposes, the taxpayer may continue to depreciate the assets, to the extent depreciable, in the manner in which the assets were being depreciated before January 1, 1985, if the higher basis is the result of:

(1) a taxable corporate liquidation before January 1, 1985;

(2) an exchange of property before January 1, 1985, that qualified under Internal Revenue Code Section 1031, but did not similarly qualify under § 12-7-930, as in effect on December 31, 1984, as a result of the property received in the exchange not having a situs in South Carolina; or

(3) Internal Revenue Code Section 179 before January 1, 1985.

(D) If a taxpayer is reporting income from a corporate liquidation distribution under Internal Revenue Code Section 337 using the installment method of reporting or from an installment sale under Internal Revenue Code Section 453, and the taxpayer has previously reported all the gain for South Carolina income tax purposes, then South Carolina taxable income must be reduced by the amount of the installment gain. If a taxpayer has elected installment sale reporting for South Carolina purposes and not federal purposes, the taxpayer shall continue to report gain on the South Carolina tax return in addition to income otherwise taxable.

(E) A taxpayer reporting income or deducting expenses over a time period as a result of a change of accounting method or accounting year, shall report income or deduct expenses in the manner provided in the Internal Revenue Code and approved by the Internal Revenue Service. At the expiration of the authorized adjustment period, the balance of the income or expense must be reported or deducted in the same manner and amount for South Carolina income tax purposes until all of the income or expenses have been fully reported or deducted.

(F) If a South Carolina taxpayer had a valid "S" election in effect for federal tax purposes before January 1, 1985, but has not elected that treatment for South Carolina income tax purposes, the taxpayer may at its option continue to be subject to the tax provided in § 12-6-530 or the taxpayer may affirmatively elect South Carolina "S" Corporation status. The election may be made by filing a statement or federal "S" Corporation election with all of the shareholders consenting to the state election or all shareholders can indicate their consent by reporting the "S" Corporation income or loss on their individual or composite South Carolina return(s).

(G) If before January 1, 1985, a taxpayer has made an election pursuant to Internal Revenue Code Section 83(b) (Election to Include Property Transferred in Connection with Performance of Services in the Year of Transfer), the election is not effective for South Carolina income tax purposes unless the taxpayer reported income in a manner consistent with the election on the South Carolina income tax return for the year of the election. Otherwise, the taxpayer is taxed under the provisions of Internal Revenue Code Section 83 when income is otherwise realized and recognized as though no Section 83(b) election had been made.

(H) An incentive stock option issued under Internal Revenue Code Section 422A is considered a qualified option or incentive stock option for South Carolina income tax purposes whether granted before or after January 1, 1985.

(I) A taxpayer may not deduct a capital loss carryover under Internal Revenue Code Section 1212 from a tax year before January 1, 1985, for South Carolina income tax purposes.

(J) A net operating loss carryforward under § 12-7-705 as in effect on December 31, 1984, is allowed for South Carolina income tax purposes before loss carryforwards pursuant to the Internal Revenue Code Section as modified by Article 9 of this chapter, but the same loss may not be deducted more than once. A net operating loss that has not expired before January 1, 1985, expires under the rules provided in Internal Revenue Code Section 172.

(K) A taxpayer receiving an annuity before January 1, 1985, that is subject to tax pursuant to Internal Revenue Code Section 72 shall continue to report income from the annuity in the manner provided in § 12-7-560(2) in effect on December 31, 1984.

(L) If a taxpayer is subject to the provisions of Internal Revenue Code Sections 483 (Interest on Certain Deferred Payments) or 1271 through 1288 (Special Rules for Bonds and Other Debt Instruments) as a result of a contract entered into before 1985, then no recomputation of principal and income is required.

(M) For a taxable year beginning after December 31, 1984, to the extent gross income, adjusted gross income, or taxable income of any taxpayer is affected by a provision of federal law enacted before January 1, 1985, which provision is not contained in the Internal Revenue Code, the provision is applicable in determining the South Carolina gross, adjusted gross, and taxable income of the taxpayer in the appropriate taxable year.