A Reexamination of Firm Size, Book-to-Market, and Earnings Price in the Cross-Section of Expected Stock Returns

Abstract

This paper reexamines the explanatory power of beta, firm size, book-to-market equity, and the earnings-price ratio for average stock returns, correcting two currently controversial biases: selection bias in COMPUSTAT and the errors-in-variables (EIV) bias. After filling in the missing data on COMPUSTAT with the Moody's sample, I do not find any significantly different results for book-to-market equity from using the COMPUSTAT sample only. After correcting for the EIV bias, I find stronger support for the beta pricing theory than previous studies. Regardless of the presence of firm size, book-to-market equity, and earnings-price ratios, betas have significant explanatory power for average stock returns. In particular, firm size is barely significant using monthly returns, but no longer significant using quarterly returns. However, book-to-market equity still has significant explanatory power for average stock returns, even though the EIV bias is corrected.