Corporation Tax Losses: Carrying Forward and Back

Making a loss isn't ideal, but understanding how to use that loss can save significant tax in other years. This guide explains corporation tax loss relief.

How Loss Relief Works

When your company makes a trading loss, you have options:

OptionWhat It Does
Carry forwardUse against future profits
Carry backClaim against previous year's profits
Group reliefTransfer to profitable group companies
Offset against other incomeUse against current year non-trading income

Types of Losses

Trading Losses

Losses from your company's main business activity. These have the most flexible relief options.

Non-Trading Losses

Losses from:

  • Property (rental losses)
  • Capital losses (asset disposals)
  • Non-trade loan relationships (investment losses)
Different rules apply to each type.

Capital Losses

From selling assets for less than cost. Can only offset capital gains, not trading profits.

Carrying Losses Forward

How It Works

If you make a loss this year, you can carry it forward to reduce profits in future years.

Example:

  • Year 1: Loss of £20,000
  • Year 2: Profit of £50,000
  • Taxable profit Year 2: £50,000 - £20,000 = £30,000

Rules for Carried Forward Losses

Pre-April 2017 losses:

  • Can only offset trading profits from the same trade
  • No time limit
Post-April 2017 losses:
  • Can offset against total profits
  • But subject to the "loss restriction" (see below)

The Loss Restriction

For accounting periods from 1 April 2017:

Your ProfitsMaximum Offset
Up to £5 million100%
Over £5 million£5m + 50% of excess
For most small companies: This doesn't apply. You can use all your losses.

Carrying Losses Back

How It Works

Carry a trading loss back to offset profits from the previous 12 months.

Example:

  • Year 1: Profit of £40,000, paid £7,600 tax
  • Year 2: Loss of £30,000
  • Carry back: Recover £30,000 × 19% = £5,700 tax

Rules for Carry Back

AspectRule
PeriodPrevious 12 months
Limit£2 million (per period)
TimingClaim in the loss-making year's CT600

Extended Carry Back (COVID Measure)

For accounting periods ending between 1 April 2020 and 31 March 2022:

  • Losses could be carried back up to 3 years
  • This was a temporary measure (now ended)

How to Claim Loss Relief

On Your CT600

Carrying forward (no immediate action needed):

  • Note the loss in your records
  • Claim when you have profits to offset
Claiming carried forward losses:
  • Box 275: Trading losses used against trading profits
  • Box 285: Non-trading deficits used
Carrying back:
  • Complete supplementary page CT600A
  • Shows the loss and which period you're carrying back to

Timing

Claim TypeWhen to Claim
Carry forwardWhen using (future CT600)
Carry backIn loss-making year's CT600
Group reliefBoth companies must claim

Practical Examples

Example 1: Simple Carry Forward

Year 1: Loss £15,000 Year 2: Profit £25,000

Year 2 CalculationAmount
Profit£25,000
Less: Loss b/f(£15,000)
Taxable profit£10,000
Tax at 19%£1,900
Without loss relief, tax would be £4,750. Saving: £2,850

Example 2: Carry Back

Year 1: Profit £50,000, tax paid £9,500 Year 2: Loss £35,000

Carry Back ClaimAmount
Year 1 profit£50,000
Less: Loss carried back(£35,000)
Revised profit£15,000
Revised tax£2,850
Tax to recover£6,650

Example 3: Mixed Approach

Year 1: Profit £20,000 Year 2: Loss £45,000

DecisionApproach
Carry back £20,000Recover £3,800 tax
Carry forward £25,000Use when profitable

Strategic Considerations

When to Carry Back

  • You need cash now (refund)
  • Tax rates were higher in previous year
  • Uncertainty about future profits

When to Carry Forward

  • Expecting higher profits (and potentially higher rates) in future
  • Don't need immediate cash
  • Previous year's profits were low anyway

Planning Points

  1. Consider marginal relief - Rates between £50k-£250k profit mean timing matters
  2. Time limits - Carry back claims must be made within 2 years
  3. Group relief - May be more valuable than carry forward

Property Losses

Different Rules Apply

Property rental losses can:

  • Offset against other property income (same year)
  • Carry forward against future property income
  • Cannot offset against trading profits

Example

Trading profit: £30,000 Property loss: £10,000

The property loss cannot reduce the £30,000 trading profit. It carries forward against future property income only.

Capital Losses

Very Restricted

Capital losses (from selling assets) can only:

  • Offset capital gains in the same year
  • Carry forward against future capital gains
  • Cannot offset income profits

Example

Trading profit: £50,000 Capital loss: £20,000

The capital loss cannot reduce the £50,000 trading profit. It can only be used against capital gains.

Common Mistakes

1. Forgetting to Claim

Losses don't automatically reduce future tax. You must claim them on your CT600.

2. Losing Track

Keep records of all losses and when they arose. Different rules apply to different periods.

3. Wrong Type Offset

Trying to use property losses against trading profits, or capital losses against income.

4. Missing Time Limits

Carry back claims must be made within 2 years. After that, you can only carry forward.

5. Not Considering Groups

If you have group companies, surrendering losses might give quicker relief than carrying forward.

Frequently Asked Questions

How long can I carry losses forward?

Indefinitely for most trading losses. There's no time limit.

What if my company closes?

Terminal losses (in the final 12 months of trading) can be carried back up to 3 years.

Can I choose how much to carry back?

Yes. You can carry back part and keep part for the future. Consider which gives the best tax outcome.

Do losses ever expire?

Generally no, but:

  • If the trade changes significantly, losses may be restricted
  • If ownership changes, anti-avoidance rules may apply

What records should I keep?

  • CT600s showing losses
  • Computation showing loss calculation
  • Working showing remaining losses to carry forward

Summary

Loss TypeCarry ForwardCarry BackSpecial Rules
TradingYes (indefinite)12 monthsMost flexible
PropertyYesNoOnly vs property
CapitalYesNoOnly vs gains
Losses aren't ideal, but proper use of loss relief ensures you don't pay more tax than necessary when profits return.


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