We study firms' investment in internal controls to reduce accounting manipulation. We first show that peer managers' manipulation decisions are strategic complements: one manager manipulates more if he believes that reports of peer firms are more likely to be manipulated. As a result, one firm's investment in internal controls has a positive externality on peer firms. It reduces its own manager's manipulation, which, in turn, mitigates the manipulation pressure on managers at peer firms. Firms do not internalize this positive externality and, thus, underinvest in their internal controls over financial reporting. The problem of underinvestment provides one justification for regulatory intervention in firms' internal controls choices.

We propose a model to study how auditing standards affect audit quality. We posit that both auditors' incentives and expertise are relevant for audit effectiveness. Auditing standards are useful in mitigating the auditors' possible misalignment of interest with investors. However, auditing standards also restrict auditors' exercise of professional judgment, which, in turn, leads to compliance mentality and reduces auditors' incentives to become competent in the first place. We identify the conditions under which stricter auditing standards increase or decrease audit quality. Moreover, stricter auditing standards always increase audit fees, but can benefit auditors at firms' expense. The model also generates many testable empirical predictions.