Declining-Balance Convention

The midmonth convention allows a full month's depreciation if you place the asset in service on or before the 15th of a month; no depreciation is allowed if you place the asset in service after the 15th.

No depreciation is allowed for the disposition month if you dispose of the asset on or before the 15th of the month; a full month's depreciation is allowed if you dispose of the asset after the 15th.