Large audit firm premium and audit specialisation in the public sector

The outsourcing of public‐sector audits to the private sector is an important issue. This study examines the fee premium in the public sector by comparing audit fees between the government auditor and the Big5. The study (i) statistically adjusts for self‐selection bias, (ii) allows the slope coefficients in the audit fee model to vary between the Big5 and the government audit and (iii) estimates the counterfactual audit fee premium. The Big5 premium is around 23 percent. However, the variation in premium depends on whether the Big5 auditor is an industry or city specialist.