Question juridique clé
Whether the supplementary wealth tax under Thurgau law complied with the Tax Harmonization Act
Solution extraite
The cantonal supplementary tax mechanism was compatible with Art. 14 StHG.
Motifs extraits
The tax is levied only for the period during which the land benefited from agricultural-value taxation; it does not impermissibly double-count the market value and may be triggered upon sale even if the property had already shifted to market-value taxation.