The double declining balance depreciation (DDB) method, also known as the reducing balance method, is one of two common methods a business uses to account for the expense of a long-lived asset. The double declining balance depreciation method is an accelerated depreciation method that counts as an expense more rapidly (when compared to straight-line depreciation that uses the same amount of depreciation each year over an asset's useful life). Similarly, compared to the standard declining balance method, the double declining method depreciates assets twice as quickly.