Purpose – The purpose of this paper is to examine the nature and extent of instability of capital asset pricing model (CAPM) beta in a small emerging capital market. Design/methodology/approach – Inter‐period as well as intra beta instability are examined. Inter‐period instability is...

Purpose – The purpose of this paper is to examine the relationship between beta and returns in the Athens stock exchange (ASE), taking into account the difference between positive and negative market excess returns' yields. Design/methodology/approach – The data were taken from DataStream...