We use measures of neural activity provided by functional magnetic resonance imaging (fMRI) to test the "realization utility" theory of investor behavior, which posits that people derive utility directly from the act of realizing gains and losses. Subjects traded stocks in an experimental market...

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 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...

In this paper, we study the optimal portfolio selection problem of weakly informed traders in the sense of Baudoin \cite{Baudoin_2002}. Instead of considering only expected utility maximizers, we also take into consideration different preference paradigms. In particular, we analyze a...

We prove a general version of the super-replication theorem, which applies to Kabanov’s model of foreign exchange markets under proportional transaction costs. The market is described by a matrix-valued càdlàg bid-ask process $$(\Pi_t)_{t\in [0,T]}$$ evolving in continuous time. We propose a...

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 multivariate utility function, allowing for simultaneous consumption of any prescribed selection of the...

Behavioral finance argues that some financial phenomena can plausibly be understood using models in which some agents are not fully rational. The field has two building blocks: limits to arbitrage, which argues that it can be difficult for rational traders to undo the dislocations caused by less...

We study asset prices in an economy where some investors classify risky assets into different styles and move funds back and forth between these styles depending on their relative performance. Our assumptions imply that news about one style can affect the prices of other apparently unrelated...

One of the most striking portfolio puzzles is the %u201Cdisposition effect%u201D: the tendency of individuals to sell stocks in their portfolios that have risen in value since purchase, rather than fallen in value. Perhaps the most prominent explanation for this puzzle is based on prospect...

A number of studies have identifed patterns of positive correlation of returns, or comovement, among different traded securities. We distinguish three views of such comovement. The traditional 'fundamentals' view explains the comovement of securities through positive correlations in the rational...