Straight-Line Convention

The midmonth convention allows a full month's depreciation for the month of acquisition 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 of a month.

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