Effect of 9/11 on the conditional time‐varying equity risk premium: evidence from developed markets

Purpose - The purpose of this paper is to examine the volatility effects on the returns for six developed market indices factoring in the unprecedented event of September 11, 2001, hereafter referred to as 9/11, in the USA. It also looks at the correlations between the indices and the risk premium when uncertainty in the financial markets affects the investors psyche, eroding confidence as volatility increases. Design/methodology/approach - The volatility of the indices in generalized autoregressive conditional heteroskedasticity (GARCH) framework, employing first the Box and Jenkins ARMA (p,q) to select models is investigated. The chosen models are based on the results obtained from Akaike information criterion and Schwartz Bayesian criterion. GARCH is a mechanism that includes past variances in the explanation of future variances. Findings - The results highlight several findings, the variance of developed market returns appears to have increased after the 9/11 event; the correlation has increased among developed markets following 9/11; 9/11 affects developed markets, holding short‐term assets do not provide the investors with the reward they usually seek, but results are mixed in the case of holding long‐term assets; for all the period including sub‐period, signs of significant volatility clustering are found; but shocks are not explosive throughout. Originality/value - The effect of 9/11 on the markets is different from previous worldwide crashes, such as that of October 19, 1987. This paper will be of value to policy makers and managers/institutional investors and those who have some stakes in international portfolio diversification, as the objective of diversification, is to avail the opportunity to improve portfolio performance on the low correlations across international stock markets.