How a bond gain affects child benefit and the personal allowance

A chargeable event gain on an investment bond is income charged to tax (ITTOIA 2005 s.461), so the whole gain is part of the individual’s total income and net income for the year it arises (ITA 2007 s.23). Adjusted net income starts from net income (ITA 2007 s.58). Top-slicing relief does not take the gain back out: it is a tax reduction (ITA 2007 s.26), applied to the tax bill after income has been worked out. Every test that reads adjusted net income therefore sees the full gain, not the annual-equivalent slice.

ITTOIA 2005 s.461 · ITA 2007 s.23 · ITA 2007 s.26 · ITA 2007 s.58

The two income tests the gain can cross

The High Income Child Benefit Charge. For 2026/27 the charge starts when adjusted net income exceeds £60,000. It claws back 1% of the year’s Child Benefit for every £200 above that, rounded down to a whole percentage, and reaches 100% at £80,000. The charge falls on the partner with the higher adjusted net income, so a gain in one partner’s name can move the charge to that partner.

ITEPA 2003 s.681C · ITEPA 2003 s.681H

The personal-allowance taper. Once adjusted net income passes £100,000, the £12,570 personal allowance is reduced by half the excess until it reaches nil. The gain counts towards that excess in full, so the allowance lost on the real income for the year is set by the whole gain.

ITA 2007 s.35

HMRC’s Insurance Policyholder Taxation Manual makes the same point for age-related allowances and tax credits: there is no top slicing when income is computed for those tests, and “the full amount of the gain is included for these purposes”.

IPTM3820

Worked example: a £55,000 salary and two children

An employed parent in the rest of the UK earns £55,000 in 2026/27 and claims Child Benefit for two children for the whole year. At £27.05 a week for the eldest child and £17.90 for the second, over the 53 full benefit weeks in 2026/27, that is £2,382.35. Their partner has lower adjusted net income. The parent has no other income, makes no pension contributions or Gift Aid donations, and fully surrenders an onshore bond whose certificate shows basic-rate tax treated as paid. The chargeable event gain is £30,000 before any TAR, over 10 complete years.

Worked-example basis: No time-apportioned reduction is due for any gain or policy shown. TAR is not calculated or applied. Raw gains are shown before any TAR.

Without the gain, adjusted net income of £55,000 is below the £60,000 threshold and no charge arises. With it, adjusted net income is £85,000, past the £80,000 point, so the charge is 100% of the Child Benefit: £2,382 after rounding down to whole pounds. Top-slicing relief of £1,800 brings the tax on the gain down to £4,000; it does not change the £85,000 the charge is tested against. Adjusted net income stays under £100,000, so the personal allowance is the full £12,570. The onshore 2026/27 figures use the calculators’ qualified basis for that year: HMRC’s published 2025/26 worksheet procedure applied with 2026/27 rates, with internal penny rounding. A native 2026/27 worksheet has not been verified, so check the working independently before relying on it for a return.

Where the personal allowance comes in

Take the same gain for a parent earning £80,000. Adjusted net income is £80,000 without the gain and £110,000 with it. The child benefit charge is 100% either way, because the salary alone reaches £80,000. The gain’s effect moves to the personal allowance instead.

Worked-example basis: No time-apportioned reduction is due for any gain or policy shown. TAR is not calculated or applied. Raw gains are shown before any TAR.

Two personal-allowance figures appear here, and both are right. On the parent’s real income the allowance is tested on adjusted net income including the full gain, so it falls to £7,570 and stays there for the year. The tax on the gain after relief, £6,000, includes the tax on the allowance the gain withdrew. Inside the top-slicing calculation, HMRC recalculates the allowance on a notional income that includes only the slice, which gives £12,570 at Step 4. That recalculation is “for the purposes of the top slicing relief calculation only”: it sets the size of the relief and does not restore the allowance on the real income. The savings allowances guide covers the related recalculation of the personal savings allowance and the starting rate for savings inside the relief.

ITA 2007 s.35(2) · ITTOIA 2005 s.535 · ITTOIA 2005 s.536(1) Step 2 · IPTM3820

Running a case

The chargeable event gain calculator works out the gain and the top-slicing relief calculator works out the relief. The adjusted net income calculator totals the income, with the gain entered as other taxable income, and the High Income Child Benefit Charge calculator compares both partners’ adjusted net income and works out the charge for the partner who pays it. Grossed-up Gift Aid and relief-at-source pension contributions are deducted in arriving at adjusted net income (ITA 2007 s.58 Steps 2 and 3), so they are part of the same picture.

For the general rule that the relief leaves adjusted net income untouched, see does top-slicing relief reduce adjusted net income?; for the relief step by step, how to calculate top-slicing relief; and for the band between £100,000 and the point where the allowance runs out, the £100k tax trap, explained. For planning and illustration only; this article does not constitute financial or tax advice.