Well, strictly, if your business has a year end which straddles 31 December 2015, then it needs to buy any assets that qualify for the annual investment allowance (AIA) before 31 December 2015 in order to maximise its AIA claim.
The AIA is currently £500,000. This decreases to £200,000 from 1 January 2016. However, the rules work in a bizarre way for businesses that have accounting periods which straddle 31 December 2015. For a business with a 31 January 2016 year end the maximum AIA is 11/12 of £500,000 + 1/12 of £200,000 = £475,000. So far, so good. However, the maximum spend in January 2016 that would qualify is only 1/12 of £200,000 = £16,667!
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