Investment Risk Concepts and Measurement of Risk in Asset Returns

The theory of finance is built around return and risk concepts and a basic tenet of finance is that there is a trade off between the risk and returns of assets. As such the measurement of risk goes to the very core and foundation of the theory of finance. Given that the main theories of finance have been maturing over several decades of discussion and debate, one would imagine that a concept as fundamental as the measurement of risk would be a well settled issue by now. On the contrary, the recent finance literature shows ample evidence that risk measurement and risk concepts are drawing continued scrutiny from academic researchers. This is because there are several alternative, and competing ways in which risk can be conceived of and it is not clear which of the alternative concepts is most appropriate. Each concept of risk can be measured or estimated in several ways as well. Estimation methods can be diverse in their precision. Risk measurement can be further complicated by the fact that risk is not a static feature. Risk changes over time. Whether risk changes can be modelled satisfactorily is a major challenge taken up by researchers.