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...

Existing findings suggest that standard, frictionless, expected-utility models have difficulty accounting for average and for median holdings of wealth and of risky assets, partly as a result of the largely unexplained limited proportion of stockholders among households. We analyze life-cycle...

The literature on household asset accumulation draws a sharp distinction between "short-run" precautionary motives to buffer consumption from annual income shocks, and "long-run" life cycle considerations under income certainty. However, estimates of shock persistence imply considerable career...

This paper studies effects of two classes of borrowing constraints, collateral- and income-based, on wealth accumulation, portfolio behavior and on precautionary motives. We examine the sensitivity of solutions to tightness of constraints, education level, and preference parameters. The models...

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)...