After a long period of universal mandatory audit, the UK reduced the regulatory burden of private firms by introducing size-based audit exemption in 1994; the size thresholds have subsequently been progressively increased. Both accounting bodies and credit rating agencies have expressed reservations...

Although theory suggests that companies would rationally select into audit even if it were not a legal requirement, many countries impose mandatory audits. This is arguably due to an audit having elements of a public good, which may result in not enough audits being purchased without regulatory...