Optimal nonlinear taxation of income and savings without commitment

When a government is unable to commit to its future tax policies, information about taxpayers' characteristics revealed by their behavior may be used to extract more taxes from them in the future. We examine the implications of this ratchet effect for the design of redistributive income and savings tax policies in a two-period model with two types of individuals who only differ in their skill levels. When commitment is not possible, it may be optimal to separate, pool, or partially pool different types in period one. The nature of the distortions to labor supplies and savings are investigated for each of these three regimes. The identification of the optimal regime is investigated numerically.