Information asymmetry occurs where one party of an enterprise has more or better information than the other. The primary objective is to remove asymmetric information. It is argued that information asymmetry can be removed by a high quality audit. This study examined the differences between the enterprises audited by Big Four audit companies that were employed for measuring the quality of audit and the enterprises not put into such audit in terms of information asymmetry variables. The enterprises audited by four big audit companies, which were argued to make a high quality audit, were compared with other enterprises in terms of 6 variables used in the measurement of information asymmetry. The study was conducted on manufacturing industry enterprises traded at Istanbul Stock Exchange (Note 1). The variables of the independence of the board of directors, market value/book value, and Tobin Q were found to be statistically different in two separate enterprise groups. However, the study yielded results contrary to those reported in the literature.