Example. The principal place of Partnership A's business on the day that the notice of the final partnership administrative adjustment was mailed to A's tax matters partner was Cincinnati, Ohio. However, by the day on which a petition seeking judicial review of that adjustment was filed, A had moved its principal place of business to Louisville, Kentucky. For purposes of section 6226(a)(2), A's principal place of business is Louisville.
26 C.F.R. §301.6226(a)-1