The amount or value assigned to a taxpayer's cost of acquiring, or investment in, an asset. Primarily used when determining the taxpayer's gain or loss when the property is sold, bartered, or exchanged or the asset's depreciation. adjusted basis. The value of a taxpayer's basis in an asset, after making additions or subtractions to his or her original basis, to reflect certain events, such as capital improvements and depreciation, that affect the value of the property subsequent to the taxpay...