We develop a simple model of the exchange rate in which agents optimize their portfolio and use different forecasting rules. They check the profitability of these rules ex post and select the more profitable one. This model produces two kinds of equilibria, a fundamental and a bubble one. In a...

We survey retail investors at an online bank to study beliefs about the autocorrelation of aggregate stock returns, and how these beliefs shape investment decisions measured in administrative account data. Individuals' beliefs exhibit substantial heterogeneity and predict trading responses to...

Bubbles are omnipresent in lab experiments with asset markets. Most of these experiments were conducted in environments with only human traders. Today markets are substantially determined by algorithmic traders. Here we use a laboratory experiment to measure changes of human trading behavior if...

Suppose that a group of agents having divergent expectations can share risks efficiently. We examine how this group should behave collectively to manage these risks. We show that the beliefs of the representative agent is in general a function of the group.s wealth level, or equivalently, that...