The book-to-market equity ratio as a proxy for risk: evidence from Australian markets

Crucial to the interpretation of the Fama and French three-factor model is the question of whether the book-to-market equity ratio should be assigned as a ‘risk-based,’ as opposed to a ‘mispricing’ explanation of share price formation. In the context of Australian stock markets, we examine the role of the book-to-market equity ratio in the formation of stock returns. Notwithstanding the distinctive characteristics of Australian markets, our findings are complementary with findings for U.S. stocks. We succeed in revealing a strong association between stock returns and the firm’s book-to-market equity ratio, and find strong evidence that the association derives from the book-to-market ratio’s absorption of the implications of market leverage as a risk factor. In addition, we determine evidence of mispricing as contributing to the formation of market leverage itself.