Scholars and investors have studied the value premium for several decades. However, the debate over whether risk factors or biased market participants cause the value premium has never been settled. The risk explanation argues that value firms are fundamentally riskier than growth firms. At the same time, the behavioral explanation argues that biased market participants systematically misprice value and growth stocks. In this paper, I use the implied cost of equity capital to capture all risks that investors demand a premium and sort stocks into risk quantiles. The implied cost of equity capital is estimated using models proposed by Gebhardt et al., Claus and Thomas, Ohlson and Juettner-Nauroth, and Easton. I find that value stocks have higher implied cost of equity capital and lower forecasted earnings growth while growth stocks have lower implied cost of equity capital and higher forecasted earnings growth. More importantly, even within the same risk quantile, the value premium still exists. The results suggest that risk and behavioral factors simultaneously cause the value premium. Furthermore, by decomposing the holding period return, I find that adjustments in valuation ratios caused by negative earnings surprises for growth firms and positive earnings surprises for value firms at least partially lead to the value premium.