Basis period reform – spreading rules for payment

If your business has transitional profits from basis period reform, spreading over five years may reduce the cash flow impact, but it is important to understand the deadlines.

The self-employed basis period reform has changed the way trading income is allocated to tax years. Under these reforms, the basis of assessment moved from a current year basis to a tax year basis.

As a result, all sole traders and partnership businesses are now required to report their profits on a tax year basis. This change fully came into effect from the self-assessment return due by 31 January 2025, covering the 2023–24 tax year.

Under the old rules, businesses could have overlapping basis periods. This sometimes resulted in profits being taxed twice, with corresponding overlap relief usually given when the business ceased. The move to a tax year basis removed the basis period rules and prevented the creation of any new overlap relief.

The spreading rules for the payment of transitional profits are still available. By default, transition profits are spread evenly over five tax years, from 2023–24 to 2027–28, helping to ease cash-flow pressures. Taxpayers can also elect to accelerate the taxation of transition profits if they wish, but spreading continues to apply automatically unless an election is made.

If your business ceases on or before 5 April 2027, any transition profit remaining after overlap relief that has not yet been taxed must be brought into charge in the final year of trading.