Audits provide monitoring for investors. The collapse of markets across the financial crisis made assets more difficult to value, which increased risk for auditors. The money markets were at the center of the financial crisis increasing audit engagement risk on money market funds, which at the time of the crisis were highly opaque. Measuring the response to increased engagement risk with audit fees, this study finds that auditors increase their fees for the riskiest class of funds. However, no evidence was found that audit fees increased as funds increased their holdings in the riskiest class of securities.