Paper by Brad M. Barber, Terrance Odean, and Michal Strahilevitz
We establish two previously undocumented patterns in the purchase selections of individual investors. These patterns hinge on investors’ previous experiences with a stock. We demonstrate that investors prefer to (1) repurchase stocks they previously sold for a gain rather than stocks they previously sold for a loss and (2) repurchase stocks that have lost value subsequent to a prior sale rather than those that have gained value. We document these trading patterns by analyzing trading records for 66,465 households at a large discount broker between January 1991 and November 1996, and 665,533 investors at a large retail broker between January 1997 and June 1999. We propose that the first trading pattern results from a simple form of learning whereby investors repeat actions that previously resulted in pleasure while avoiding actions that previously led to pain (i.e., they repurchase their previous winners more readily than their previous losers). We argue that the second trading pattern is tied to counterfactuals. Investors who buy a stock at a higher price than they previously sold it for are painfully aware that they are worse off than if they had simply never sold that stock. Investors who buy a stock at a lower price than they previously sold it experience the pleasure of knowing they are better off than if they had never sold that stock. Investor returns do not benefit from either of the two patterns we document.
Investors driven by emotion, not facts [ Physorg.com ]