Sovereign rating announcements and the integration of African banking markets

Purpose The purpose of this paper is to examine the information spillover of sovereign rating changes on the market valuation of bank stocks in Africa. Design methodology First, the authors apply event study methodology to evaluate the stock market reaction of African bank stocks on the announcement of sovereign rating changes. Second, the cross sections of the abnormal returns are examined by multivariate regression analyses. Third, the findings are proved for robustness. Findings The authors investigate how 37 African banks react to 203 African sovereign rating announcements from the three leading credit rating agencies over the period 2010-2016 and find that negative announcements trigger the significant positive stock reactions of African banks, especially contributed by banks in the non-reviewed African countries. These unusual reactions can be explained by the low integration and the severe information asymmetry of African capital markets. The authors further locate the influencing factors of banks' reactions and show that rating downgrades magnify the abnormal effects while the membership of the African Free Trade Zone mildens the stock market reactions. Research limitations/implications - Limitations are given by the limited sample size. There are only limited numbers of publicly listed African banks with sufficient trading data. Practical implications - The paper argues for a critical dependency of African bank equity valuation in the case of sovereign debt rating changes in neighbor countries. This observation is important for the risk assessment of African banking assets. Originality/value The paper is the first to examine stock market reactions on sovereign rating announcements for the evaluation of capital market integration in Africa. It thereby underlines the usefulness of this simply to apply approach as an instrument for ongoing examining the progress in capital market development in emerging countries.