Switching Investments Can Be a Bad Idea When Parrondo's Paradox Applies

Abstract

Many studies have indicated that a buy-and-hold investment strategy is superior to a trading strategy. This is thought to be true because trading incurs transaction costs that lower net returns compared to a buy-and-hold strategy. We propose a behavioral finance argument to illustrate that merely switching between positive expected return assets can lead to a long-run negative expected return, even when transaction costs are ignored. This counterintuitive result may obtain because of Parrondo's Paradox. We provide a stylized theoretical example that demonstrates how a trader can lose money by trading between assets with positive long-run expected returns. We also present simulation results to support our example. Thus, long-run negative results from trading may not be due entirely to transaction costs. A trading strategy may prove inferior to buy-and-hold for agents simply because of their singular trading patterns, as we outline in the paper.