We create an experimental asset market in which the value of the shares is independent of the quantity outstanding, and find that (i) repurchases increase, whereas share issues decrease, the price of the asset. These effects are consistent with downward-sloping demand for the asset. (ii) This behavior is consistent with three trader types—fundamental, speculator, and momentum—interacting in the market. (iii) Share issues drive prices down toward, but not beyond, fundamental values. This downward resistance at the fundamental value is predicted by the impact of an intervention on the proportion of units and cash held by each trader type.

A series of experiments illustrate that relaxing short‐selling constraints lowers prices in experimental asset markets, but does not induce prices to track fundamentals. We argue that prices in experimental asset markets are influenced by restrictions on short‐selling capacity and limits on the cash available for purchases. Restrictions on short sales in the form of cash reserve requirements and quantity limits on short positions behave in a similar manner. A simulation model, based on DeLong et al. (1990) , generates average price patterns that are similar to the observed data.

Experimental data have consistently shown diversity in beliefs as well as in actions among experimental subjects. This paper presents and compares alternative behavioral econometric models for the characterization of player heterogeneity, both between and within subpopulations of players. In particular, two econometric models of diversity within sub-populations of players are investigated, one using a model of computational errors and the other allowing for diversity in prior beliefs around a modal prior for the subpopulation.

We elicit traders' predictions of future price trajectories in repeated experimental markets for a 15-period-lived asset. We find that individuals' beliefs about prices are adaptive, and primarily based on past trends in the current and previous markets in which they have participated. Most traders do not anticipate market downturns the first time they participate in a market, and, when experienced, they typically overestimate the time remaining before market peaks and downturns occur. When prices deviate from fundamental values, belief data are informative to an observer in predicting the direction of future price movements and the timing of market peaks.