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...

We relate the degree of investor portfolio focus to the broader urban economic context of the household. Using a detailed panel of investors in Sweden over the period 1995 to 2000, we find that the level of investor diversification, as measured by number of stocks in the portfolio and by the...

We study how competition in the mutual fund industry affects stock market liquidity. We argue that mutual fund families operate as multi-product firms, jointly choosing fees, performance and number of funds and sharing common research facilities. The family-based organization generates economies...

We study the puzzle of portfolio underdiversification and proximity investment from a novel perspective, linking it to the process of urbanization. We find that urban portfolios are more focused – i.e., less diversified and more concentrated in ‘close’ stocks. We explain it in terms of the...

We exploit the restrictions of intertemporal portfolio choice in the presence of non-financial income risk to design and implement tests of hedging that use the information contained in the actual portfolio of the investor. We use a unique dataset of Swedish investors with information broken...

In this thesis we explore two recent topics in behavioral finance, namely portfolio optimization by non-expected utility insiders and existence of equilibria in financial markets populated by heterogeneous agents. Firstly, we review a number of theories which have been used to model behavioral...

In this paper we deal with a utility maximization problem at finite horizon on a continuous-time market with conical (and time varying) constraints (particularly suited to model a currency market with proportional transaction costs). In particular, we extend the results in Campi and Owen (2011)...

In this article, we characterize efficient portfolios, i.e. portfolios which are optimal for at least one rational agent, in a very general financial market model with proportional transaction costs. In our setting, transaction costs may be random, time-dependent, have jumps and the preferences...

Using a novel data of institutional investors' bond holdings, we examine a transmission of the crisis of 2007-2008 from the securitized bond market to the corporate bond market via joint ownership of these bonds by investors. We posit that, ceteris paribus, corporate bonds held by investors with...

We present an optimal investment theorem for a currency exchange model with random and possibly discontinuous proportional transaction costs. The investor’s preferences are represented by a smooth, multivariate utility function, allowing for simultaneous consumption of any prescribed selection...