Overconfidence is the most prevalent judgment bias. Several studies find that overconfidence can lead to suboptimal decisions on the part of investors, managers, or politicians. This chapter explains which effects are usually summarized as overconfidence, shows how to measure these effects, and...

Using German and US brokerage data we find that investors are more likely to sell speculative stocks trading at a gain. Investors' gain realizations are monotonically increasing in a stock's speculativeness. This translates into a high disposition effect for speculative and a much lower...