(1) "Determination" means:

(a) A decision by the Oregon Tax Court that has become final;

(b) A closing agreement made under ORS 305.150;

(c) A final disposition by the Department of Revenue of a claim for refund. For purposes of this paragraph, a claim for refund shall be deemed finally disposed of by the department as to items with respect to which the claim was allowed, on the date of allowance of refund or credit or on the date of mailing notice of disallowance (by reason of offsetting items) of the claim for refund, and as to items with respect to which the claim was disallowed, in whole or in part, or as to items applied by the department in reduction of the refund or credit, on expiration of the time for instituting suit with respect thereto (unless suit is instituted before the expiration of such time); or

(d) Under regulations prescribed by the department, an agreement for purposes of ORS 314.105 to 314.135 signed by the department and by any person, relating to the liability of such person (or the person for whom the person acts) in respect of a tax for any taxable period.

(2) "Related taxpayer" means a taxpayer who, with the taxpayer with respect to whom a determination is made, stood, in the taxable year with respect to which the erroneous inclusion, exclusion, omission, allowance, or disallowance was made, in one of the following relationships:

(a) Spouses in a marriage;

(b) Grantor and fiduciary;

(c) Grantor and beneficiary;

(d) Fiduciary and beneficiary, legatee, or heir;

(e) Decedent and decedent’s estate;

(f) Partner;

(g) Member of an affiliated group of corporations as defined in section 1504 of the Internal Revenue Code; or

(h) Shareholder of an S corporation, as defined in section 1361 of the Internal Revenue Code.

(3) "Taxpayer" means any person or entity subject to tax under an applicable revenue law. [1971 c.248 §2; 1984 c.1 §15; 1985 c.602 §1; 1987 c.758 §11; 2005 c.94 §75; 2015 c.629 §35]