We respond to calls for research into the effect of the decline in the number of Big N firms on market power and consequential impact on competition (U.S. Department of Treasury 2008; European Commission 2010; U.K. House of Lords 2011) by analyzing the change in Big N audit fee premium over the Big 6,...

Globally, companies increasingly publish separate general purpose, non-financial (sustainability) reports. Some of these are independently assured and assurers may or may not be from the auditing profession. We seek to understand this emerging voluntary assurance market. Using a sample of 2,113...