Self-employed taxpayers with a year end other than 31 March or 5 April will be affected by the move to a tax year basis. They will need to establish any overlap relief available to them ahead of filing their self assessment returns for the transitional year, 2023/24.

HMRC can only provide this information if it is recorded in HMRC’s systems and has been included within submitted returns for previous tax years.

ICAEW understands that where overlap profit has not been recorded, HMRC will also provide data that allows the taxpayer or agent to work out the overlap relief (eg, the self-employment data from the relevant tax returns) where this is available from HMRC’s systems.

If any taxpayers wish to make a request ahead of publication of this online form, HMRC will require the following information:

• customer name;
• national insurance number or unique taxpayer reference (UTR);
• name or description of the business;
• whether the business is a sole trader or partnership;
• if the business is part of a partnership, the partnership’s UTR;
• date of commencement of the self-employed business, or date of commencement as a partner in a partnership (if not known, then the tax year of commencement); and,
• the most recent accounting period end date.
  
  

Read more about the transition to the tax year basis:

• Basis period reform: explaining the changes
• TAXguide 02/22: Basis Period Reform
• How HMRC assesses profits for some sole traders and partnerships to change
• BIM81200 - Tax year basis and transitional rules: contents - HMRC internal manual