Oregon Revised Statutes Revenue and Taxation § 314.140

(1) Whenever there has been an adjustment of federal income tax liability involving a reallocation of any item of income or deduction between related taxpayers, and when such adjustment results in the assessment of a tax deficiency or the issuance of a refund check or both, then for Oregon income tax purposes, whether or not the Department of Revenue effects a similar reallocation of income or deduction for the same tax year, said federal tax deficiency and additions thereto shall be deducted (to the extent otherwise provided by law) by the taxpayer paying the same, and said federal tax refund, including interest thereon, shall be returned (to the extent otherwise required by law) by the taxpayer receiving the same.

(2) If, however, the related taxpayers involved (or their authorized representatives) so elect in accordance with subsection (3), then the refund of one, with interest thereon, shall be treated as a reduction of the deficiency of the other, including additions thereto, so that only the net amount of deficiency shall be deducted or the net amount of refund shall be returned, as the case may be.

(3) An election under subsection (2) shall be in writing, signed by each related taxpayer or authorized representative, and filed with the department prior to the expiration of the applicable period of limitation with respect to the adjustment of the last open state return of either related taxpayer affected by the federal tax deficiency or refund. Such election shall constitute a waiver of any statute of limitations to permit the adjustment of all returns of the related taxpayers for the purpose only of effecting a reallocation of income or deductions similar to that made by the federal tax authorities and to adjust the federal income tax deductions resulting therefrom.