We obtain data from SEC filings and SDC for 589 mergers and acquisitions in the U.S. for announced between 1998 and 2005 for which we are able to determine the numbers and identities of all parties acting as financial advisers and providing fairness opinions regarding the transaction to the target and acquiring firms. We develop measures of the degree of moral hazard to which the firms may have been subject based on the numbers of advisers fulfilling the roles of financial adviser and fairness opinion provider in each case. We then use these measures in multiple regression models of post-acquisition firm performance to test the hypothesis that performance is negatively related to moral hazard, as Sarbanes-Oxley (SOX) has implicitly assumed. We find a significant, negative relation between both the level of moral hazard and the degree of moral hazard and acquiring firm abnormal returns on the announcement of the acquisitions. However, our preliminary findings indicate that moral hazard may not have influenced outcomes differentially following implementation of SOX.