This thesis consists of three essays. The first essay, “A Theory of Bank Illiquidity and Default with Hidden Trades”, develops a theory of banking to explore how the availability of trading opportunities for both banks and individual investors affects the link between illiquidity and default in the financial system. The results show that default emerges only in the presence of systemic risk, and when an unpredicted crisis hits the economy. Moreover, in contrast to the previous literature, default is not an efficient outcome of the economy. The second essay, “Financial Liberalization with Hidden Trades”, studies how the availability of unregulated market-based channels for the circulation of liquidity in the financial system affects the proc...