The subprime financial crisis, the Gulf oil leak, and the Madoff scandal -- are three concern rare occurrences with catastrophic consequences. These seemingly unrelated events occurred because those involved did not adequately recognize the risk. These events show that managers, in their day-to-day business dealings, must perform an enterprisewide risk assessment at least annually to identify events that could affect the business negatively and take adequate steps to prevent, avoid or mitigate the consequences of negative events, however remote they may seem. Even unlikely events can involve massive intervention after the fact that costs governments, investors and innocent victims billions. Timely recognition of the risks involved and effective oversight may have prevented one or more of these tragedies.