Capital Flow Watch

Depreciation is a term used in accounting, economics and finance to spread the cost of an asset over the span of several years. In accounting, however, depreciation is a term used to describe any method of attributing the historical or purchase cost of an asset across its useful life, roughly corresponding to normal wear and tear. It is of most use when dealing with assets of a short, fixed service life, and which is an example of applying the matching principle per generally accepted accounting principles. Depreciation in accounting is often mistakenly seen as a basis for recognizing impairment of an asset, but unexpected changes in value, where seen as significant enough to account for, are handled through write-downs or similar techniques which adjust the book value of the asset to reflect its current value.
The use of depreciation affects the financial statements and in some countries the taxes of companies and individuals. The recording of depreciation will cause an expense to be recognized, thereby lowering stated profits on the income statement, while the net value of the asset (the portion of the historical cost of the asset that remains to provide future value to the company) will decline on the balance sheet. Depreciation reported for accounting and tax purposes may differ substantially.
Depreciation and its related concept, amortization (generally, the depreciation of intangible assets), are non-cash expenses. Neither depreciation nor amortization will directly affect the cash flow of a company, as both are accounting representations of expenses attributable to a given period. In accounting statements, depreciation may neither figure in the cash flow statement, nor be “added back” to net income (along with other items) to derive the operating cash flow. Depreciation recognized for tax purposes will, however, affect the cash flow of the company, as tax depreciation will reduce taxable profits; there is generally no requirement that treatment of depreciation for tax and accounting purposes be identical. Where depreciation is shown on accounting statements, the figure usually does not match the depreciation for tax purposes.
Because of its non-standardized derivation, depreciation is a key component of EBITDA, a metric used to gauge the worth of a company independent of tax-jurisdiction effects and capitalization structure. (Wikipedia Jan 2010)