Federal Court Judgment No. 2C_953/2019, April 14, 2020. Valuation of unlisted securities for wealth tax purposes (Art. 14 para. 1 LAID). Circular No. 28 of the Swiss Tax Conference pursues the goal of horizontal tax harmonization, thus concretizing Art. 14 para. 1 LAID and is recognized by consistent case law as an appropriate and reliable method.