Transaction costs and the small firm effect

Recent empirical work by Banz (1981) and Reinganum (1981) documents abnormally large risk-adjusted returns for small firms listed on the NYSE and the AMEX. The strength and persistence with which the returns appear lead both authors to conclude the single-period, two-parameter capital asset pricing model is misspecified. This study (1) confirms that total market value of common stock equity varies inversely with risk-adjusted returns, (2) demonstrates that price per share does also, and (3) finds that transaction costs at least partially account for the abnormality.