监管保护下的审计业务量效应

The Audit Business Scale Effect of Regulatory Activities

在声誉和赔偿等机制的作用下，如果高业务量的审计方将因机会主义行为而损失更多，则会降低机会主义行为的概率，从而产生审计业务量效应。本文则试图为监管引致的审计业务量效应提供理论分析和经验证据。当监管方为保护投资者而集中取缔违规者的从业资格，不仅惩罚了已有的错失，还示范了审计业务量和机会主义成本的正相关性，即严重损害投资者利益的行为将导致所有的市场业务的丢失，从而激发审计方业务量和其后续机会主义概率的关联性。在此理论预期下，本文的检验结果表明，当“从业资格取缔”型监管事件发生，审计方的业务量越高，其客户公司的短期超额回报也更高，暗示当监管通过抑制未来的机会主义概率而对投资者形成保护时，激发了审计方的业务量和机会主义审计行为的关联度的信念，投资者根据审计业务量调整了对客户公司的价值预期。结论有助于我们理解监管的“惩前治后”的示范性质和其引发审计业务量效应的可能性。

The motivation of large auditors to engage in opportunistic behaviour will be lower if their potential losses from damage to reputation and litigation penalties are higher. This paper aims to provide a theoretical analysis of and empirical evidence for the question of whether the audit business scale effect （ABSE） may result from audit regulation. In 2002, five CPA finns were disqualified because of audit failures or violation of professional rules. I conduct an event study and find that the more businesses an auditor has, the higher the cumulative abnormal return （CAR） its clients will have. Such a finding reveals that investors will revise their expected market value of listed firms in accordance with the auditor＇s business scale. A possible explanation is that both investors and auditors receive a signal for a positive relation between the audit business scale and the cost of misconduct from such regulatory activities, since opportunistic behaviour will cost each dishonest auditor the loss of all its businesses. When investors expect that large auditors will have greater incentive to provide high quality audits because they have more businesses at risk as a result of regulation, the market values of listed firms with large auditors will thereby increase. Taking everything together, this paper indicates that audit regulation leads to ABSE, since regulators can wam honest audit firms while punishing dishonest ones.