This dissertation is a collection of two essays relating to the dynamic effects of taxation.

In the first chapter, I focus on a key challenge faced by tax reforms: their short-run

welfare consequences. I examine a consumption-based tax reform that, despite the long-run welfare gains it generates, causes the welfare for some groups such as retirees or the working poor to fall during transition between steady states. Using a life-cycle model with heterogeneous households, I show how to devise a transition path from the current U.S. federal tax system to a consumption-based tax system that improves the welfare of current generations as well as those who are born in the long-run steady state. In a nutshell, all households alive at the time of the policy change can choose when they want to switch to the new tax system, or whether they want to switch at all. I find that implementing a tax reform with this feature improves the welfare of 95% of the population in the short run, compared to less than 25% of population in the conventional case with no choice. It takes about 20 years for half of the population to pay their taxes under the new tax code.

In the second chapter, I study the aggregate consequences of the differential tax treatments of U.S. businesses focusing on the role of legal forms of organization. I develop an industry equilibrium model in which the organizational form is an endogenous choice.

This model incorporates the key trade-off that businesses face when choosing their legal forms: the tax treatment of the business income; the access to external capital, and the potential level and evolution of productivity over time.

The model is matched to the firm dynamic features of U.S. businesses and the contributing share of each legal form in total output. Using the model, I study revenue-neutral tax reforms in which legal forms receive the same tax treatments, and

I find that the incentives induced by tax structure for organizational form and external finance are both large. Relative to the benchmark economy, unifying the tax code for all legal forms, can lead to 8% increase in the aggregate output.