In order to assist in the processing of a corporation's amended income tax return, corporations must use OTC Form 512X for tax years prior to 2013. Beginning with tax year 2013, OTC Form 512 must be used and the appropriate box indicating that the return is an amended return must be marked.The documentation described in (1) through (4) of this subsection must be included, when applicable, or an explanation when not applicable, or the refund may be denied:

1. (1) Copy of the Federal Form 1120X or 1139. If the taxpayer files a federal consolidated income tax return, Form 1120X must detail the changes by entity.
2. (2) Proof of disposition by the Internal Revenue Service.
3. (3) Copy of complete Revenue Agent's Report. If the taxpayer files a federal consolidated income tax return, the Revenue Agent's Report must detail the changes by entity.
4. (4) Schedule of NOL carryback/carryover.

Amended at 18 Ok Reg 2810, eff 6-25-01

Amended at 38 Ok Reg 1527, eff 9-1-21