In this thesis we deal with different topics in financial mathematics, that are all related to market imperfections and to the fundamental technique of utility maximization. The work consists of three parts. In the first one, which is based on two papers, we consider the problem of optimal...

Stocks with large increases in call implied volatilities over the previous month tend to have high future returns while stocks with large increases in put implied volatilities over the previous month tend to have low future returns. Sorting stocks ranked into decile portfolios by past call...

We study the inflation hedging ability of individual stocks. While the poor inflation hedging ability of the aggregate stock market has long been documented, there is considerable heterogeneity in how individual stock returns covary with inflation. Stocks with good inflation-hedging abilities...

Can banks maintain their advantage as liquidity providers when they are heavily exposed to a financial crisis? The standard argument - that banks can - hinges on deposit inflows that are seeking a safe haven and provide banks with a natural hedge to fund drawn credit lines and other commitments....

Hedge funds often impose lockups and notice periods to limit the ability of investors to withdraw capital. We model the investor's decision to withdraw capital as a real option and treat lockups and notice periods as exercise restrictions. Our methodology incorporates time-varying probabilities...

Regime switching models can match the tendency of financial markets to often change their behavior abruptly and the phenomenon that the new behavior of financial variables often persists for several periods after such a change. While the regimes captured by regime switching models are identified...

Since the after-fee returns of funds-of-funds are, on average, lower than hedge fund returns, it is easy to conclude that funds-of-funds do not add value compared to hedge funds. However, funds-of-funds should not be evaluated relative to hedge fund returns in publicly reported databases....

International equity returns are characterized by episodes of high volatility and unusually high correlations coinciding with bear markets. We develop models of asset returns that match these patterns and use them in asset allocation. First, the presence of regimes with different correlations...

This Paper studies equilibrium asset pricing with liquidity risk (the risk arising from unpredictable changes in liquidity over time). It is shown that the required return on a security depends on its expected illiquidity, the covariances of its own return, illiquidity with market return, and...

We use portfolio theory to quantify the efficiency of state-level sectoral patterns of production in the United States. On the basis of observed growth in sectoral value added output, we calculate for each state the efficient frontier for investments in the real economy, the efficient Sharpe...