Are the ‘Big Six’ ‘big’ in Belgium?

Studies in the United States, Europe and Australia have shown that the market for audit services is highly concentrated and largely dominated by the same ‘Big Six’ international audit firms. This paper measures the degree of concentration in the Belgian audit market through an empirical study of the number of professionally qualified auditors employed by each audit firm and some characteristics of their clients. Our calculations show that the concentration ratios, however measured, are low when compared with other countries, possibly due to the low value attached to the certification of financial statements by a professionally qualified auditor. This lack of importance can be explained by characteristics of the Belgian environment (e.g. a relatively passive capital market, dominated by a few large holding companies) which may induce companies to chose cheaper (domestic) audit firms. We also calculate Spearman rank correlations between the rankings of the audit firms based upon the different audit firm revenue proxies. All the correlations show it is of no importance which measure is used to rank audit firms.