Conservative traders, natural selection and market efficiency

This paper examines the impact of conservative traders on market efficiency in an evolutionary model of a commodity futures market. This paper shows that the long-run market outcome is informationally efficient, as long as in every period there is a positive probability that entering traders are more conservative than their predecessors. Conservative traders are those who correctly predict the spot price with a positive probability, and more importantly, who in their mistakes err on the side of caution, and rarely overpredict the spot price as buyers, and underpredict the spot price as sellers. This result does not require entry of traders with better information than their predecessors. © 2011 Elsevier Inc. All rights reserved. JEL classification: G13; G14; D8