Facts
Spouses A.A. and B.A. née C. had their tax domicile in the Canton of Graubünden until mid-April 2007. Shortly before moving to the Canton of Zug, the husband received a pension lump-sum payment of CHF 649,860 on 3 January 2007. The Canton of Zug assessed this payment in its tax assessment of 11 July 2012, but indicated that the tax sovereignty lay with the Canton of Graubünden. The latter then issued a supplementary tax assessment for this lump-sum payment on 8 April 2014.Considerations
The Federal Supreme Court decided that pursuant to Art. 216 para. 1 DFTA 1990, the Canton of Graubünden, as the canton of domicile at the time the lump-sum payment became due, was responsible for assessing and taxing it. The regulation in Circular No. 5 of the Federal Tax Administration, according to which the canton where the payment became due is responsible, proves to be contrary to federal law. However, the Canton of Zug was able to interrupt the statute of limitations with its declaration of lack of jurisdiction of 11 July 2012, so that…