Auditor industry specialization, client bargaining power, and audit pricing

Porter's (1985) analysis of competitive strategy is used to explain industry specialization by Big 6 accounting firms. In Porter's framework, industry specialization can be viewed as a differentiation strategy whose purpose is to create a sustainable competitive advantage relative to nonspecialist auditors. A differentiation strategy will lead to higher audit fees if valued by clients. We find evidence of higher fees for Big 6 industry specialists relative to nonspecialists in the U.S. audit market, but only for companies in the lower halt of the sample based on size (assets < $123 million). By contrast, companies in the upper half of the sample do not pay a specialist premium, and audit fees actually decrease as a company becomes increasingly large relative to its auditor's industry clientele. Together these results suggest that audit fees are higher when clients are small and have little bargaining power, but audit fees are lower when clients have greater bargaining power and this is more likely when companies are large in absolute size and large relative to their auditor's industry clientele.