Capital allowances — new 40% first-year allowance

At Budget 2025, the government announced a 40% first-year allowance for qualifying expenditure incurred on plant or machinery on or after 1 January 2026.

We’ll update the Corporation Tax online service in April 2027 to support the new allowance by including 2 new boxes on form CT600.

To claim the relief before then, you can use the existing capital allowance boxes on form CT600. Use:

• boxes 725 or 750 for claim amounts

If you do not need to report this new relief, you can file online in the normal way.

The 100% first-year allowance for qualifying expenditure on zero-emission cars and electric vehicle charge points has been extended to 31 March 2027 for Corporation Tax purposes.

A small number of companies may not be able to report their claim for these allowances in the relevant CT600 boxes if they both:

• have an accounting period starting on or after 1 April 2026
• intend to submit their tax return before 1 April 2027

We’ll update the Corporation Tax online service in April 2027 to support the extended period for claiming these first-year allowances.

If you need to submit a claim for an accounting period beginning before 1 April 2026, you can continue to use the existing boxes:

• electric vehicle charge points (boxes 713 and 737)

If you need to submit a claim for an accounting period beginning on or after 1 April 2026, report your claim in boxes 725 and 750 (other allowances and charges) for both the:

• electric vehicle charge point allowance

Research and Development expenditure credit (RDEC) claims

HMRC introduced the Submit information to support your Research and Development (R&D) claim form on 8 August 2023. You must submit this for all claims for Research and Development (R&D) tax relief or expenditure credit.

Research and Development expenditure credit claims which are exempt from the PAYE cap

The merged scheme R&D expenditure credit and enhanced R&D intensive support replaced the old RDEC and small and medium-sized enterprise schemes for accounting periods beginning on or after 1 April 2024.

We are aware of an issue with the validation for the new boxes allowing customers to claim exemption from the PAYE cap under the merged scheme.

A company can only claim to be exempt if they’re creating or managing intellectual property under section CTA09/S1112E of the Corporation Tax Act (CTA) 2009.

If you’re claiming an exemption, make sure the amount entered in box L75 equals the amount entered in box L70. This is so the amount of step 3 restriction is carried forward to the next accounting period in box L80 is ‘0’.

We’ll update the service in April 2027 to fix this issue.

Creative industries

HMRC introduced the Support your claim for creative industry tax reliefs form on 1 April 2024. You must submit this for all claims for creative industry tax reliefs or creative industry expenditure credits alongside the Company Tax Return.

The Corporation Tax online service has now been updated to support the supplementary page CT600P. If you’re claiming one or more of the creative reliefs and credits, you must include the CT600P with your return. This applies to both new and amended claims.

Cultural Reliefs and Film, High End TV, Children’s TV, Animation and Video Games tax relief

We are aware of an issue with the validation which impacts a small number of customers claiming one or both of the reliefs for Cultural reliefs and Film, High End TV, Children’s TV, Animation and Video Games reliefs, and:

• have no losses to surrender in column D
• are not claiming any tax relief in column E

The entry in column E must be less than the entry in column D. The service will not accept a zero in both of these columns for boxes P260 to P305.

In these cases you should enter £1.00 in column D so your return can be accepted. This will not affect the validity of your claim.

The service will be updated in April 2027 to fix this issue.

The sections of the CT600P relating to Audio-Visual and Video Games Expenditure Credit are not affected.

Loans to participators

At Budget 2025, the rate of tax payable under the loans to participators regime was increased from 33.75% to 35.75%. The new rate will apply to loans made or benefits conferred on or after 6 April 2026.

Find more information in the Corporation Tax Act 2010 section 455 and Corporation Tax Act 2010 section 464A.

The Corporation Tax online service will be updated to reflect this change on 6 April 2027.

If the new rate applies to your company and you need to file before 6 April 2027, you’ll need to amend your return after 6 April 2027 to reflect the new rate.

New requirements for Company Tax Return computation format

Most companies need to include a computation when submitting their Company Tax Return. This computation:

• is typically generated by your accounting software
• includes the necessary eXtensible Business Reporting Language (XBRL) tagging

HMRC is developing a standardised format for the computation. This is to improve consistency, support better quality data and provide clear expectations for software developers, agents, and businesses.

Published specifications:

We have published the first specifications for 2 areas of the computation:

We will not require computations to be submitted in this format until phase 2 of the work to develop the requirements has been completed, and a timetable for the changes has been confirmed.

Timeline for implementation

We’re working with software developers, accountants, business groups and businesses to decide what information will be needed. Before any requirement becomes mandatory, we’ll explain when you need to use the new format, and how to use it. We’ll also provide enough time for software developers, agents and businesses to prepare for the changes

What you need to do

For more information about the proposed requirements, read the file CT Computations Format. You should treat this as an information document while we continue to develop the requirements.