Deferred tax represents a company's liability for taxes owed that is postponed to future periods. Deferred tax is primarily the result of tax law that allows firms to write off expenses faster than they are recognized and thus create a deferred tax liability. For example, under tax law companies can often depreciate fixed assets at a faster rate for tax purposes than the actual use of the asset would dictate. Theoretically, the resulting difference between income under Generally Accepted Accounting Principles and income for tax purposes sets up a deferred tax liability for the apparent taxes owed to the IRS in the future. In actual practice, the deferred tax liability may be postponed indefinitely if the company continues to buy new equipment. Over the past decades, accounting standards for deferred tax have been revised substantially. The rules for deferred tax remain complex and, in some circles, controversial. Some observers argue that deferred tax is merely an accounting fiction and that no deferred tax should be recognized, because the only tax liability is the amount actually owed to the IRS.