An Investigation into the Firm Size Effect: A Security Market Plane Approach

Abstract

This paper tests the firm size effect with two different approaches. First, the “messy” and “clean” methods of Fama and French are used; the firm size effect is found to remain but only after the regression residuals are analyzed. Then a security market plane and a proxy of it are defined and the proxy security market plane is used for testing. The results indicate that the firm size effect is reliably detected and statistically “explained” by a proxy security market plane for the sample period from July 1963 to June 1986.