Basis period reform affects partnerships and self employed people whose accounting year does not end on or between 31 March or 5 April.

Up to 5 April 2023, the basis period reporting rules applied. This means profits were reported in line with the business accounting year end date within the relevant tax year.

From 6 April 2023, the new tax year basis applies. This means profits will need to be reported up to the tax year end, even if the accounting year ends at a different time. As a result profits may need to be apportioned between accounting periods.

The 2023-24 tax year is known as the ‘transition year’. This means sole traders and partnerships will have to: