Facts
The spouses [A.A.] and [A.B.] are owners of a 992 m2 plot of land in [U.] /SO, on which they built a detached single-family house and an annex building. The investment costs amounted to around CHF 1.3 million. The Tax Office of the Canton of Solothurn (KStA/SO) set the imputed rental value of the two buildings for the 2013 tax period at CHF 33,630.-- each. The taxpayers lodged an objection and claimed that the imputed rental value was correctly CHF 27,615.-- per year. The KStA/SO dismissed the objection. The taxpayers appealed to the Cantonal Tax Court of Solothurn, which partially upheld the appeal and set the imputed rental value at CHF 28,185.--.
The KStA/SO lodged a complaint with the Federal Supreme Court and requested that the imputed rental value be set at CHF 33,630.-- per year. The taxpayers and the lower court requested that the complaint be dismissed.
Considerations
The Federal Supreme Court examined the scope of the reference to the guidelines issued by the FTA in § 9 para. 2 StO/SO No. 15. It found that the provision applies to buildings of above-average construction and that the reference to the FTA's guidelines is to be considered as supplementary law.
The court concluded that the reference in § 9 para. 2 StO/SO No. 15 is static and that the 1969 circular should also be used in the tax periods 2010 to 2016. It found that the contrary interpretation and application of the cantonal…