Written by Oroni Chowdhury · Last reviewed: November 2026 · Applies to the 2026/27 tax year
A chargeable event certificate lands on the doormat after you cash in a bond, and suddenly your tax return shows a bill far bigger than you expected. Often the reason is that top slicing has not been applied, or the wrong figure has gone in the wrong box.
This guide explains top slicing from the point of view of the person filing the return. It covers who qualifies, how HMRC works out the relief, three checked 2026/27 examples, how to report the gain, the adjusted net income trap and what changes from April 2027.
- Top slicing reduces the tax on a bond gain; it does not reduce the gain itself.
- Only individuals can claim. Trustees, companies and personal representatives cannot.
- Enter the full gain on your return, never the slice.
- HMRC’s calculation applies the relief from the figures you give, so check it.
- The full gain still counts towards adjusted net income.
- Savings tax rates and the onshore tax credit change from 6 April 2027.
What Is Top Slicing?
Investment bonds and life insurance policies let growth build up for years without tax. The tax arrives in one go when a “chargeable event” happens. A gain built up over a decade can then land in a single tax year and push you from basic rate into higher rate (HS320 gains on UK life insurance policies).
Top slicing softens that. It compares the tax on the whole gain with the tax you would pay if only an average year’s share, the “slice”, sat on top of your other income, multiplied back up by the number of years. If the slice route gives less tax, the difference is your relief.
Two points trip people up. Top slicing is a reduction in tax, not a smaller gain. And a bond gain is income, not a capital gain, so the Capital Gains Tax annual exempt amount and capital losses cannot be used against it.
What counts as a chargeable event?
- Cashing in the whole policy (a full surrender)
- A part surrender, including withdrawals above the 5% a year you can normally take without an immediate charge
- The policy maturing
- The death of the life assured, where that ends the policy
- Selling or assigning the policy for money
Who Can and Can’t Claim Top Slicing Relief
The relief is for individuals only (IPTM3820). If someone else is taxed on the gain, there is no top slicing.
| Who is taxed on the gain | Top slicing relief? |
|---|---|
| An individual policyholder | Yes |
| Trustees of a trust | No |
| A company | No (company rules apply instead) |
| Personal representatives after a death | No |
| Annual gains on a personal portfolio bond | No |
If you are unsure who the taxable person is, for example on a bond held in trust, read the certificate carefully and take advice before filing. Eternity Accountants has a fuller explainer on how top slicing relief works.
How Top Slicing Relief Is Worked Out
HMRC sets out the method for a single gain in five steps (IPTM3840 how relief is given). In plain terms:
- Add the full gain to your other income and see which bands it falls into, including the starting rate for savings and the Personal Savings Allowance.
- Work out the tax on the full gain and take off any basic-rate tax treated as already paid. This is your total liability.
- Divide the gain by the number of complete years (N) to get the slice.
- Work out the tax on the slice in the same way, take off tax treated as paid on the slice, then multiply by N. This is the relieved liability.
- Your relief is the total liability minus the relieved liability.
Counting the years (N)
Your chargeable event certificate gives the number of years, but it helps to know where it comes from (IPTM3830). For a full surrender, N is usually the number of complete years since the policy started. For a part surrender or an excess over the 5% allowance, N can run only from the last time a gain arose. Years spent abroad can reduce it, and N is never less than 1.
How allowances are treated in the slice
Since the Finance Act 2020 changes, your Personal Allowance is worked out on your income including only the slice, not the full gain, when calculating the relieved liability. For gains from 2021/22, the starting rate for savings and the Personal Savings Allowance are also recalculated on the slice. This often makes the relief larger than older guides suggest.
Several gains in the same year
If you have gains from more than one policy in the same tax year, HMRC does not run the five steps separately for each. It adds the gains together for the full calculation, works out each policy’s own slice using its own N, and adds the slices to find the relieved liability. Give each gain and its years accurately on the return.
Years spent abroad
If you were not UK resident for part of the time you held the policy, time apportionment relief may reduce the gain first. The relief is then worked out on what is left. The certificate will not always reflect this, so check your residence history before filing.
Top Slicing Worked Examples for 2026/27
The examples below use 2026/27 rates for England, Wales and Northern Ireland. All figures are illustrative and calculated step by step.
Ravi earns a salary of £48,000. He cashes in a UK (onshore) investment bond with a gain of £30,000 after 5 complete years. Basic-rate tax of 20% is treated as already paid on the gain.
| Step | Full gain | Slice |
|---|---|---|
| Total income | £78,000 | £54,000 |
| Personal Savings Allowance (0%) | £500 | £500 |
| At 20% (rest of basic band) | £1,770 = £354 | £1,770 = £354 |
| At 40% | £27,730 = £11,092 | £3,730 = £1,492 |
| Tax before credit | £11,446 | £1,846 |
| Less tax treated as paid | £6,000 | £1,200 |
| Liability | £5,446 | £646 × 5 = £3,230 |
Top slicing relief is £5,446 − £3,230 = £2,216. Ravi pays £3,230 extra tax on the gain instead of £5,446.
Notice that the relief here is smaller than people often expect. Ravi’s salary already uses most of the basic rate band, so even the slice spills into higher rate. Top slicing helps most when the slice fits entirely within the basic rate band and the full gain does not.
If Ravi’s bond had been an offshore bond, no tax would be treated as paid. The full calculation gives £11,446 and the slice gives £1,846 × 5 = £9,230.
The relief is still £2,216, and he pays £9,230. The higher bill reflects that an offshore fund has not already paid UK tax on its growth.
Reporting Top Slicing on Your Self Assessment Return
Most mistakes happen when the gain is entered on the return. HMRC’s calculation will work out the relief, but only from the figures you give it (HS320).
- Read the certificate. Your insurer must send a chargeable event certificate showing the gain, the number of complete years and whether tax is treated as paid.
- Find the right section. Online, gains go in “Other UK income”, under gains from life insurance policies, capital redemption policies and life annuity contracts. On paper, use the SA101 additional information pages.
- Enter the full gain, in the box for gains with tax treated as paid (onshore) or without (offshore), plus the number of years.
- Combine gains from more than one policy in the same year. HMRC uses a separate method for several gains, so give each one accurately.
- Check the calculation before you submit, as explained below.
Is the relief automatic?
Broadly, yes. If you report the gain and the years correctly, HMRC’s Self Assessment calculation includes the relief (help with other UK income). It is still worth checking the figure against the five steps, especially with large gains, several gains or a Personal Allowance near the £100,000 taper. Third-party software can treat unusual cases differently.
A quick way to check HMRC’s figure
Look at the tax calculation HMRC produces after you enter the gain. It should show the tax on the full gain, then a separate line reducing it for top slicing relief. If there is no reduction and the gain pushed you into a higher band, check the number of years first, as a missing or wrong N is the most common cause. Then compare the result with your own working using the five steps above.
If the figures still do not match, keep a note of your working. It makes any later amendment or conversation with HMRC much quicker.
Filed without the relief?
You can usually amend an online return within 12 months of the 31 January filing deadline. After that, an overpayment relief claim may be possible within 4 years of the end of the tax year. If you need to check other dates, see our guide to Self Assessment deadlines.
A later loss: deficiency relief
If a policy ends with a loss after earlier gains were taxed, deficiency relief may reduce tax on your other income. It is limited to the lower of the earlier gains and the loss, does not work against the additional rate, and is only available to individuals. HMRC’s helpsheet explains the calculation.
When to get help
Get help if a bond was held in trust, if you were abroad during the policy, if you had several gains in one year, or if the gain pushes you close to £100,000. Each of these changes the calculation in ways the standard steps do not show.
The Adjusted Net Income Trap
The relief cuts the tax on the gain, but it does not reduce your income. The full gain still counts when working out adjusted net income, the figure HMRC uses for the High Income Child Benefit Charge and the Personal Allowance taper above £100,000.
Sophie earns £52,000 and claims Child Benefit. She cashes in a bond with a £30,000 gain, so her adjusted net income becomes £82,000.
- The relief may reduce the Income Tax on the gain.
- Her adjusted net income is above £80,000, so the whole of her Child Benefit is repaid through the High Income Child Benefit Charge.
- Without the gain, her income of £52,000 is below the £60,000 starting point and no charge would apply.
The timing of a surrender can therefore matter as much as the relief itself. Pension contributions and Gift Aid can reduce adjusted net income, but get advice before relying on them.
The same effect applies around £100,000, where every £2 of adjusted net income above that level removes £1 of Personal Allowance in the full calculation.
What Changes for Top Slicing From April 2027
Bond gains are taxed as savings income, so changes to savings rates feed straight into the calculation. The method stays the same, but the numbers move.
| Change from 6 April 2027 | Status |
|---|---|
| Savings income rates rise to 22%, 42% and 47% | Finance Act 2026 |
| A further rise to 24%, 44% and 49% for savings income | Announced in the Budget on 28 October 2026; not yet law |
| Basic-rate tax treated as paid on onshore bonds rises from 20% to match the basic savings rate | Follows the savings rate change |
Savings income is taxed at UK rates even for Scottish taxpayers, so these figures apply across the UK. Check current Income Tax rates before you file a 2027/28 return. This guide explains the rules; it is not advice on when to cash in a bond.
Mistakes to Avoid
| Mistake | What happens | How to avoid it |
|---|---|---|
| Entering the slice instead of the full gain | Income and tax are understated | Enter the full gain and the years |
| Missing a gain from a withdrawal above 5% | An unreported chargeable event | Check every certificate for the year |
| Treating the gain as a capital gain | Wrong section, wrong tax | Report it as savings income |
| Ignoring adjusted net income | A surprise Child Benefit charge or lost allowance | Check the gain against £60,000 and £100,000 |
| Assuming a trust bond gets the relief | Tax underestimated | Trustees cannot claim top slicing |
Top Slicing: FAQs
What is top slicing in simple terms?
It is a relief that taxes a bond gain as if it had been spread over the years you held the bond, so a one-off gain does not push all of it into a higher band.
Is top slicing relief automatic?
HMRC’s Self Assessment calculation applies it when you enter the full gain and the number of years. You should still check the figure.
Do I enter the full gain or the slice?
The full gain. Entering the slice understates your income and leads to the wrong tax.
Does top slicing apply to offshore bonds?
Yes. The method is the same, but no tax is treated as paid on an offshore bond, so the final bill is usually higher.
Can trustees claim top slicing relief?
No. Trustees, companies and personal representatives cannot claim it. Only individuals can.
Does top slicing reduce adjusted net income?
No. The full gain counts towards adjusted net income, which can trigger the High Income Child Benefit Charge or reduce your Personal Allowance.
What changes in April 2027?
Savings income rates rise from 6 April 2027, and the basic-rate tax treated as paid on onshore bonds is expected to rise with them.
What if I filed without the relief?
Amend the return within 12 months of the filing deadline, or consider an overpayment relief claim within 4 years.
Final Verdict: Getting Top Slicing Right on Your Return
Top slicing can cut the tax on a bond gain by thousands of pounds, but only if the full gain and the right number of years go on your return. Check HMRC’s figure against the five steps, watch the knock-on effect on Child Benefit and your Personal Allowance, and allow for the savings rate changes from April 2027.
- Find your chargeable event certificate and note the gain, years and tax treated as paid.
- Enter the full gain on your return and check the relief against the five steps.
- Check whether the gain affects Child Benefit or your Personal Allowance.