The first chapter presents a theoretical model of asset pricing that analyses how the behavior of stock returns is affected by the presence of regret averse investors in the market. The model predicts market over-reaction on good or bad news, and an excess volatility of stock returns. It helps to explain such well-established empirical puzzles as the positive short-run and negative long-run autocorrelation of stock returns, and it predicts a positive correlation between future trading volume and the dispersion of stock returns. The framework developed in this chapter helps to analyze how an improvement of stock market accessibility affects the predictability of stock returns. Using stock market data, this chapter also presents an empirical ...