ABSTRACT This study provides evidence of a directly observable and significant cost of International Financial Reporting Standards (IFRS) adoption, by examining the fees incurred by firms for the statutory audit of their financial statements at the time of transition. Using a comprehensive dataset of all publicly traded Australian companies, we quantify an economy-wide increase in the mean level of audit costs of 23 percent in the year of IFRS transition. We estimate an abnormal IFRS-related increase in audit costs in excess of 8 percent, beyond the normal yearly fee increases in the pre-IFRS period. Further analysis provides evidence that small firms incur disproportionately higher IFRS-related audit fees. We then survey auditors to construct a firm-specific measure of IFRS audit complexity. Empirical findings suggest that firms with greater exposure to audit complexity exhibit greater increases in compliance costs for the transition to IFRS. Given the renewed debate about whether the Securities and Exchange Commission (SEC) should mandate IFRS for U.S. firms, our results are of timely importance. Data Availability: Data are publicly available from the sources identified in the paper. Survey response data are available from the authors upon request.

We use a long time-series from Australia to shed light on economic factors that led to audit market concentration and the Big N. We show that increases in the size of a small number of public companies was an important factor that led to large audit firms and market concentration. We also show that emerging Big N firms made sunk cost investments, including in the ability to provide industry expertise and non-audit services, which allowed them to retain clients, differentiate, and grow. These changes occurred around the time the profession lifted restrictions on advertising, which helped facilitate differentiation, and that larger, more complex clients switched to emerging Big N firms while smaller clients switched to non-Big N firms. We do not find that increases in audit market concentration reduced competition; our results instead suggest the audit market became more competitive over time.