We use a long time-series from Australia to shed light on economic factors that led to audit market concentration and the Big N. We show that increases in the size of a small number of public companies was an important factor that led to large audit firms and market concentration. We also show that emerging Big N firms made sunk cost investments, including in the ability to provide industry expertise and non-audit services, which allowed them to retain clients, differentiate, and grow. These changes occurred around the time the profession lifted restrictions on advertising, which helped facilitate differentiation, and that larger, more complex clients switched to emerging Big N firms while smaller clients switched to non-Big N firms. We do not find that increases in audit market concentration reduced competition; our results instead suggest the audit market became more competitive over time.

We use unique disclosures in the insurance industry to examine whether client-engaged specialists (i.e., external actuaries) affect opportunism within the claim loss reserve. Using a fixed-effects approach, we find that external actuaries significantly affect the opportunism in the claim loss reserve, approaching half the effect of the auditor. With respect to actuary characteristics, we find a positive (negative) association between actuary permissiveness (actuary size) and opportunism in the claim loss reserve. In additional analyses, we find that the relation between actuary permissiveness and claim loss reserve opportunism is stronger when insurers have incentives to opportunistically manage the claim loss reserve. This relation continues to persist in the presence of high-quality auditors. Overall, we provide evidence suggesting that client-engaged external actuaries can be used to support opportunistic claim loss reserve estimates.