In the first chapter, I investigate the welfare effect of the government subsidizing medical insurance. To that extent, I construct and simulate a partial equilibrium computational model of medical care consumption and choice of insurance contracts. I use the overall utility of agents as a welfare measure and find that it is not welfare improving to subsidize uninsured agents by taxing insured ones. In addition I use the framework to verify the insurance contract choice effect and find a strong insurance contract choice effect. In Chapter 2, I investigate the effect of the price setting process under managed health care plans, such as HMOs and PPOs, on prices, profits of insurance companies and medical care providers, and household’s welfare compared to the indemnity plans prevalent before the advent of managed care. I construct a simple game played between a representative insurance company and a medical care provider to determine the price of medical care paid by insured and uninsured households. In addition, insurance companies set premiums not through solving the usual principal-agent problem which forces a zero profit condition, but rather and more realistically by optimizing profits. The outcome of this game is compared to the outcome of the indemnity plans where no price negotiations would occur. In Chapter 3, I investigate the effect of the suggested reform to the United States’ tax code in treatment of housing assets. In particular, I study the effect of the abolishment of the preferential tax treatment of housing assets (tax deductible mortgage interest payments and tax-free imputed rents) on the ownership and foreclosure rates in the housing market. I construct a model where heterogeneous agents decide on housing tenure in which default on housing mortgages occurs in equilibrium. I use this model to quantify the effect of this preferential tax treatment. I find that the elimination of the preferential tax treatment of housing assets results in a 33.4% reduction in foreclosures. Specifically, only eliminating the tax deductibility of interest on mortgage payments leads to a 12.4% reduction in foreclosure rates, while only taxing imputed rents generates a 32.5% reduction in foreclosure rates. / text