Abstract The main objective of the current study is the examination of the relationship between beta and returns in the Athens Stock Exchange, taking into account the difference between positive and negative market excess returns' yields. We investigate the period between 1991 and 2002 focusing on the risk-return trade-off by examining separately the up-market and down-market months. We try to verify whether beta is an important measure of risk and if there is an inverse relationship between beta and returns when the return on the market is negative. We also investigate if there is any symmetry between up and down market returns in the ASE. The estimation of return and beta without differentiating positive and negative market excess returns produces a flat unconditional relationship between return and beta. Using the conditional CAPM and cross-sectional regression analysis, the evidence in this paper tends to support the significant positive relationship in up market and a significant negative relationship in down market. This is a second attempt in testing the relationship between beta and returns in the ASE, using single stocks instead of forming portfolios (first attempt). Although the new results are similar to those of the previous study they are definitely sounder, improved, and statistically significant. Finally, we get better results, also, when we use portfolios and the MLE method for the estimation of beta coefficients of each stock. (JEL G12)
