Fundamentals, momentum, and bubbles in experimental asset markets

Purpose – The purpose of this paper is to report the results of a study concerning how fundamental-motivated investors, and their subsequent impact on the path of prices, affect the severity of price bubbles in an experimental laboratory asset market. Design/methodology/approach – In a laboratory experiment, asset markets are manipulated by systematically replacing inexperienced human traders with automated traders programmed to submit bids and asks at fundamental value. Findings – When traders in a market are automated to invest on fundamentals, deviations from fundamental value are initially suppressed, but reappear when automated traders cease to influence prices. A significant reduction in the severity of the resulting bubble may be attributed to the interaction of automated traders and humans through the initial path of prices when controlling for changes in liquidity. This reduction corresponds to reduced autocorrelation in the time series of returns. Originality/value – This paper represents the first attempt (to the authors’ knowledge) to extend the intervention approach of the seminal paper by Smith et al. (1988) to systematically study the extent to which manipulation of initial path of prices impacts the formation and magnitude of bubbles in the laboratory.