Declining-Balance Convention

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

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

Note: For a monthly accounting cycle, the 15th day of the month is considered the midpoint of the period.