While concentration measures are a good indicator of market structure, the link with competitiveness is more complex than often assumed. In particular, the modern theory of industrial organisation makes no clear statement regarding the impact of concentration on competition ‐ the focus of this...

Prior research suggests that Big 4 auditors provide higher quality audits by virtue of their large size. Still, the recent reforms mandated by the Sarbanes Oxley Act – by increasing client and auditor incentives for accurate reporting – may have narrowed audit quality differences across...