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Interest Restriction Return (IRR) end-to-end service guide

Version 0.5 issued 16 June 2021


Overview

When calculating how much UK corporation tax a company or group has to pay, there’s a limit to the amount of tax relief allowed for deducting interest and other financing costs.

On 1st April 2017, new Corporate Interest Restriction (CIR) legislation came into effect. New rules were introduced to limit tax deduction for interest expense and other similar financing costs.

If a group has more than £2 million (per annum) in net interest expense, they may be subject to a restriction under the rules. If so, it is usually beneficial for the group to appoint a reporting company (within twelve months of the end of the period of account), to submit returns on behalf of the group. This may be the case even where the group only consists of one company.

The appointed reporting company must then submit a group level interest restriction return on behalf of the group. The deadline for submitting the return is usually twelve months from the end of the CIR period of account.

This guide explains how you can use the Interest Restriction Return API with your software

It is written for software developers, designers, analysts, managers and others involved with creating or integrating software that connects to this API.

The API supports the following functions:

  • Revoke an existing Reporting Company from submitting Interest Restriction Returns
  • Appoint a new Reporting Company for submitting Interest Restriction Returns
  • Submit an Interest Restriction Return (full)
  • Submit an Interest Restriction Return (abbreviated)

For more information about how to develop your own client applications, including example clients for this API, see Tutorials.

Business rules and error messages

You can open the business rules and error messages for each journey. They are formatted in CSV or Microsoft Excel (xlsx).

Business rules

  • Revoke an existing Reporting Company from submitting Interest Restriction Returns business rules [csv | xlsx]
  • Appoint a new Reporting Company for submitting Interest Restriction Returns business rules [csv | xlsx]
  • Submit an Interest Restriction Return (full) business rules [csv | xlsx]
  • Submit an Interest Restriction Return (abbreviated) business rules [csv | xlsx]

Error messages

  • Revoke an existing Reporting Company from submitting Interest Restriction Returns error messages [csv | xlsx]
  • Appoint a new Reporting Company for submitting Interest Restriction Returns error messages [csv | xlsx]
  • Submit an Interest Restriction Return (full) error messages [csv | xlsx]
  • Submit an Interest Restriction Return (abbreviated) error messages [csv | xlsx]

User restricted endpoints

This application uses user restricted endpoints. This means that we require specific authorisation from the user to grant authority to your application to interact with HMRC on their behalf, without sharing their access credentials.

For in depth information about user restricted endpoints, together with examples on how to integrate with them, please visit HMRC’s developer hub guidance on User Restricted Endpoints

Changelog

Version 0.5

16 June 2021

What changed:

  • Alterations to overview
  • Update business rules & error messages

Version 0.4

3 June 2021

What changed:

  • Add more information to overview
  • Add XLSX download option
  • Update content of error messages and business rules

Version 0.3

28 May 2021

What changed:

  • Add content to user restricted endpoints section

Version 0.2

24 May 2021

What changed:

  • Add overview
  • Add business rules CSVs
  • Add error messages CSVs

Version 0.1

5 March 2020

What changed:

  • Initial Draft Service. Hello World for IRR.