In accounting, expense has a very specific meaning. It is an outflow of cash or other valuable assets from a person or company to another person or company. This outflow of cash is generally one side of a trade for products or services that have equal or better current or future value to the buyer than to the seller. Technically, an expense is an event in which an asset is used up or a liability is incurred. In terms of the accounting equation, expenses reduce owners' equity. The International Accounting Standards Board defines expenses as
An important issue in accounting is whether a particular expenditure is classified as an expense, which is reported immediately on the business's income statement; or whether it is classified as a capital expenditure or an expenditure subject to depreciation, which is not an expense. These latter types of expenditures are reported as expenses when they are depreciated by businesses that use accrual-basis accounting, which is most large businesses and all C corporations.
The most common interpretation of whether an expense is of capital or income variety depends upon its term. Viewing an expense as a purchase helps alleviate this distinction. If, soon after the "purchase", that which was expensed holds no value then it is usually identified as an expense. If it retains value soon and long after the purchase, it will be viewed as capital with life that should be amortized/depreciated and retained on the Balance Sheet.
Even if something qualifies as an expense, it is not necessarily deductible. As a general rule, expenses are deductible if they relate to a taxpayer’s trade or business activity or if the expense is paid or incurred in the production or collection of income from an activity that does not rise to the level of a trade or business (investment activity).
Section 162(a) of the Internal Revenue Code is the deduction provision for business or trade expenses. In order to be a trade or business expense and qualify for a deduction, it must satisfy 5 elements in addition to qualifying as an expense. It must be (1) ordinary and (2) necessary (Welch v. Helvering, 290 U.S. 111, defines this as necessary for the development of the business at least in that they were appropriate and helpful). Expenses paid to preserve one’s reputation do not appear to qualify (Welch v. Helvering). In addition, it must be (3) paid or incurred during the taxable year. It must be paid (4) in carrying on (meaning not prior to the start of a business or in creating it) (5) a trade or business activity. To qualify as a trade or business activity, it must be continuous and regular, and profit must be the primary motive.
Section 212 of the Internal Revenue Code is the deduction provision for investment expenses. In addition to being an expense and satisfying elements 1-4 above, expenses are deductible as an investment activity under Section 212 of the Internal Revenue Code if they are (1) for the production or collection of income, (2) for the management, conservation, or maintenance of property held for the production of income, or (3) in connection with the determination, collection, or refund of any tax.
In investing, one controversy that mounted throughout 2002 and 2003 was whether companies should report the granting of stock options to employees as an expense on the income statement, or should not report this at all in the income statement, which is what had previously been the norm.