Carrying Forward Company Trading Losses in 2026: How UK Corporate Tax Loss Relief Works

There are a significant number of reliefs available to UK businesses that suffer losses. Where a company has unused losses that have not been set against profits in any other way, these may be carried forward to offset against profits in future accounting periods.

This mechanism is known as corporate tax loss carry forward and forms part of wider corporate tax relief rules under HMRC Corporation Tax legislation. In general, a company can carry trading losses forward as long as the trade continues, allowing future profits to be reduced for tax purposes.

However, HMRC applies restrictions on the use of carried-forward tax losses, particularly for accounting periods starting on or after 1 April 2017. These rules remain relevant in current Corporation Tax compliance practice.

This guide explains how loss carry forward works, HMRC restrictions, and how businesses apply relief in practice.

In 2026, unused trading losses continue to be a key part of UK Corporation Tax planning, particularly where businesses are looking to manage future profitability. These rules also become relevant where corporate tax exit opportunities or corporate disposals are being considered as part of longer-term restructuring.

What Is Corporate Tax Loss Carry Forward?

Corporate tax loss carry forward allows companies to use unused trading losses from previous accounting periods to reduce taxable profits in future years.

This relief is only available where:

• The company continues to carry on the same trade
• The losses have not already been used against earlier profits
• The losses are correctly calculated under HMRC Corporation Tax rules

The calculation is based on taxable profits, not accounting profits, meaning HMRC adjustments are required before relief can be claimed.

How Loss Carry Forward Works

Where a company makes a trading loss, it may carry that loss forward to reduce taxable profits in future accounting periods once the business becomes profitable again.

Example: A company incurs a trading loss due to restructuring costs. In the following year, it returns to profitability and uses the carried-forward loss to reduce its Corporation Tax liability.

When a business returns to profitability after making a loss, the carried-forward relief allows earlier losses to reduce future taxable profits under corporate tax loss carry forward rules. In some cases, this also influences decisions around corporate tax exit opportunities, depending on timing and business structure.

HMRC Restrictions on Carried Forward Losses

HMRC introduced restrictions from accounting periods starting 1 April 2017 to limit how carried-forward losses can be used.

These rules ensure that large profits are not fully eliminated by historic losses.

The restrictions generally apply as follows:

• A £5 million allowance applies before restrictions are considered
• After this allowance, only up to 50% of remaining profits can be relieved using carried-forward losses

These rules apply across most types of carried-forward losses and must be applied correctly in tax computations.

How to Claim Corporate Tax Loss Carry Forward

Claims are made through the Company Tax Return (CT600), using HMRC-compliant tax computations.

Key steps include:

• Preparing adjusted Corporation Tax computations
• Identifying eligible carried-forward trading losses
• Applying HMRC restriction rules where relevant
• Submitting the claim via the CT600
• Maintaining supporting documentation for HMRC review

Corporate Disposals and Exit Planning Considerations

This area of corporate tax loss carry forward can become relevant during restructuring or business exit planning.

In some cases, losses may form part of broader planning around corporate disposals or corporate tax exit opportunities, particularly where ownership changes or strategic restructuring occurs.

However, HMRC rules strictly govern how these losses can be used and they cannot be applied outside Corporation Tax calculations.

During business restructuring, corporate tax loss carry forward can play a role in wider planning around corporate disposals and potential corporate tax exit opportunities. However, HMRC rules strictly control usage, so losses cannot be applied outside permitted Corporation Tax calculations.

HMRC Risks and Compliance Issues

Common risks include:

• Incorrect calculation of carried-forward losses
• Failure to apply restriction rules correctly
• Confusion between accounting and taxable losses
• Insufficient documentation for HMRC review

Errors may result in repayment of relief, interest charges, and penalties depending on HMRC assessment.

Why Loss Carry Forward Matters

Proper use of corporate tax loss carry forward supports long-term tax efficiency and financial planning.

It helps businesses reduce future Corporation Tax liabilities, improve recovery after loss-making periods, and manage tax exposure across accounting cycles.

For long-term planning, corporate tax loss carry forward helps businesses smooth tax liabilities across profitable and loss-making years. It is also relevant when considering corporate disposals or evaluating corporate tax exit opportunities as part of strategic financial planning.

Corporate Tax Loss Carry Forward Support for Strategic HMRC Planning in 2026

Understanding corporate tax loss carry forward rules is essential for UK companies looking to manage taxable profits efficiently while remaining fully compliant with HMRC. Trading losses can often be carried forward to offset future profits, but the relief must be applied correctly within corporation tax computations to avoid errors or rejected claims. At Cigma Accounting, we support businesses across  Kingston upon Thames, helping them structure loss utilisation in line with current UK tax legislation.

For companies planning growth, restructuring, or sale, effective use of corporate tax exit opportunities can significantly impact overall tax outcomes. Losses and reliefs must be carefully reviewed during corporate disposals, as timing and classification can influence the final tax position. We assist businesses in Hinchley Wood and Long Ditton, ensuring loss carry forward strategies are aligned with long-term planning and HMRC requirements for 2026.