The process of reducing part of the balance of an asset due to occurrence of some economic event that negatively impacted the asset’s value. That part is charged as an expense or loss account.  In this sense, it is a partial write-off. An example is the destruction or obsolescence of part of the inventory.

The writing-down process involves the reduction in the book value/ carrying amount of an asset when its fair market value (FMV) has dropped below its book value/ carrying value, rendering it an impaired asset.