How can governments design policies that alleviate the macroeconomic implications of financial frictions? This dissertation contributes to answer this question focusing on two aspects: international borrowing and crisis prevention at the country\u27s level, and the impact of taxation and financial regulation on entrepreneurship at the agent\u27s level. In the first chapter, debt crises arise from the incompleteness of sovereign debt markets: the government cannot credibly commit to repay or default in certain states of the world and this gives way to non-fundamental debt crises. In a strategic default environment, I show that international reserve holdings help to reduce the probability of these market-driven debt crises, advancing the theo...