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The Conditional Relation between Beta and Returns: Evidence from a Frontier Market


Capital Asset Pricing Model (CAPM) is one of the most significant finance literature models, which assumes a positive linear relationship between the required rate of return and systematic risk on stocks. The model is frequently used in the business world, but empirical tests repeatedly reject the model's validity in its unconditional form. Pettengill et al. have developed an alternative conditional CAPM approach where the unconditional test procedure developed by Fama & MacBeth, (1973) is improved by taking up and down market conditions. This paper investigates both the conditional and unconditional versions of CAPM in both individual and portfolio stock returns between January 2008 and December 2019 on the stocks listed in the Colombo Stock Exchange (CSE). Population of this research includes all the companies listed on CSE and the top 50 stocks with large market capitalization has been selected as the sample. The results of unconditional test procedure show that there is no statistically significant risk-return relationship is found in any test period in both individual and portfolio stock returns. Thus, this result is similar with the previous literature findings. The results of the conditional tests show that there is no significant positive (negative) risk-return relationship in portfolio stock returns and individual stock returns in CSE during up (down) market months. But findings indicate a significant positive risk-return relationship in individual stock returns in upmarket periods; whereas, a significant inverse risk-return relationship is not provided in down market periods.

Keywords: Colombo Stock Exchange, CAPM, Conditional Relation, Unconditional Relation