ABSTRACT In December 1999, the SEC instituted a new listing standard for NYSE and NASDAQ firms. Listed firms were now required to maintain fully independent audit committees with at least three members. In July 2002, the U.S. Congress legislated these standards through the Sarbanes-Oxley Act. Our research question is whether all investors benefited from the 1999 new rule. Using both an event study and a difference-in-differences methodology, we find no evidence of higher market value or better financial reporting quality resulting from this rule.

We examine the effects of the 1998 merger of Price Waterhouse ( PW ) and Coopers & Lybrand ( CL ) on the audit quality of the merged firm PricewaterhouseCoopers (PwC) at both the firm and office levels, where audit quality is surrogated by the auditor's propensity to issue a going‐concern opinion, clients’ likelihood of meeting or beating analysts’ earnings forecasts, and clients’ accrual quality. At the firm level, we find that the merger increased audit quality for PwC relative to the audit quality of the other Big N firms. At the office level, our findings, albeit mixed, collectively suggest that the improvement in firm‐level audit quality was likely driven by the improvement in audit quality at PwC's overlapping offices, that is, offices in cities where both PW and CL had separate offices prior to the merger. Further, our findings suggest that although the PW / CL merger increased auditor concentration in local audit markets with PwC overlapping offices, the merger improved (rather than hurt) audit quality in those markets. Overall, our study contributes to the extant sparse literature on the effect of Big N mergers on audit quality, and is of potential interest to regulators.