Can We Beat the Market with Beta? An Intuitive Test of the CAPM

Based on a strict and intuitive methodology, the article proposes an empirical test of the CAPM for the main Spanish market stocks. The idea is to replicate the behaviour of an investor purchasing undervalued shares according to the CAPM in order to beat the market during the following period. Where the investor does not meet his objective, the results are consistent with market efficiency and with the CAPM, as the stocks would quickly adapt to their rational value, according to the model. Otherwise, a strategy to beat the market would have been found, obtaining returns above those expected for a given level of systematic risk. Our results are consistent with market efficiency and with the CAPM. This conclusion is reached in different ways, indicating the robustness of the procedure