Occasionally, companies make mistakes in their accounting records, Sometimes these “mistakes” occur because of intentional or fraudulent misapplication of accounting rules, principles, or estimates. For example, in the spring of 2002 internal auditors at WorldCom uncovered a massive accounting fraud in which the company capitalized operating expenses and began depreciating them rather than expensing them in the year they occurred. In a case like this, the company will have to restate its financial statements and adjust numerous accounts in order to clean up its books.