Facts
The [A. AG] , a real estate company based in [U.] , was subject to a final tax assessment by the tax administration of the Canton of Zug for the 2012 tax period. At the same time, other cantons, in particular the City of Zurich and the municipality of Greifensee, levied property gain taxes. The [A. AG] lodged an objection against these assessments and received an assessment proposal during the objection procedure, which led to a change in the original assessment.
On 28 March 2018, the [A. AG] filed a request for revision with the tax administration of the Canton of Zug, in which it claimed an over-taxation of its corporate profit. The tax administration did not consider the request for revision, as the 90-day deadline after discovery of the reason for revision had already expired. The cantonal legal remedies lodged against this decision were unsuccessful.
The [A. AG] then appealed to the Federal Supreme Court and requested the annulment of the judgment of the Administrative Court of the Canton of Zug and the remittal of the matter for substantive consideration of the request for revision. The tax administration and the Administrative Court of the Canton of Zug requested the dismissal of the appeal.
Considerations
The Federal Supreme Court examined whether the lower court had rightly not considered the request for revision. It found that the [A. AG] had already discovered the reason for revision, namely inter-cantonal double taxation, with the issuance of the tax assessment decisions on 17 November 2015 and 23 October 2017.
The lower court had argued that the tax assessment decisions clearly and unambiguously showed on what basis and to what extent taxation took place in the respective municipality of the Canton of Zurich. The issuance of these tax assessment decisions had already caused current double taxation, as the tax administration of the Canton of Zug had already definitively taxed the [A. AG] for the…