Key legal question
Whether an ESTV ruling binds the Canton of Solothurn for state tax purposes
Extracted holding
The ESTV ruling had no binding effect for cantonal state tax because the ESTV's supervisory role under the direct federal tax regime does not extend to cantonal taxation.
Extracted reasoning
Only the cantonal tax authorities were competent to assess the matter in advance for state tax. A federal administrative ruling cannot bind the canton, even under good-faith or tax-harmonization arguments.