Tax policy has become a hotly disputed and politically dividing issue in the Czech Republic over the last years, culminating in a major public-finance reform. At the same time, risk and uncertainty have turned into a buzzword for virtually any discussion on economical and social topics, without actually being incorporated in most mainstream analytical tools. This research study undertakes the onerous task of addressing both of these problems. In its course, a stochastic model for the valuation of the fiscal claim is developed and used to analyze the incidence of tax under income uncertainty for a set of corporate and personal income tax schedules. This allows for a comprehensive comparative analysis of various fiscal structures, where an elaborate case is made of recent Czech legislative developments and their presumable impacts. Further applications of the model are also being discussed, ranging from business valuation and investment analysis to fiscal budgeting. This suggests that the option-based approach may serve as a useful heuristic to address numerous tax-related problems.