The AIA gives a 100% write-off on most types of plant and machinery costs, including integral features and long life assets but not cars, of up to £200,000 p.a. for expenditure incurred on or after 1 January 2016. The previous rate was £500,000 p.a. Special rules apply to accounting periods straddling this date.
Any costs over the AIA fall into the normal capital allowance pools below. The AIA may need to be shared between certain businesses under common ownership.
The annual rate of allowance is 18%. An 8% rate applies to expenditure incurred on integral features and on long life assets.
A 100% first year allowance may be available on certain energy efficient plant and cars, including expenditure incurred on new and unused zero emission goods vehicles.
For expenditure incurred on cars, costs are generally allocated to one of the two plant and machinery pools. Cars with CO2 emissions not exceeding 130gm/km receive an 18% allowance p.a. Cars with CO2 emissions over 130gm/km receive an 8% allowance p.a.