Why is the effective marginal rate 62% above £100,000?

Above £100,000 adjusted net income, you lose £1 of the £12,570 Personal Allowance for every £2 earned (fully tapered at £125,140). That extra PA loss is taxed at 40%, giving an effective marginal rate of 40% IT + 2% NI + (£1 PA × 40%) = 62%. The next £25,140 of income is taxed at 62% combined.

Does pension sacrifice reduce adjusted net income?

Yes - salary sacrifice pension contributions reduce gross pay before Income Tax is calculated. Personal pension contributions through relief-at-source also reduce adjusted net income for the £100,000 calculation (see HMRC Helpsheet HS345 Adjusted net income).

Does Gift Aid reduce adjusted net income?

Yes - donations made under Gift Aid are deducted from adjusted net income for the £100k taper calculation. The donation is grossed-up by the Gift Aid 25% bonus first, then deducted (so £100 donation = £125 gross-up = £125 deduction).

Is the £100k trap real or just optics?

Real and material. Plus Tax-Free Childcare and 30 free childcare hours are withdrawn at £100,000 - for parents the effective rate spikes past 100% on small slices of income (a £1,000 pay rise can produce zero net gain after losing TFC).

£100k Tax Trap Escape: 4 Playbook Moves for 2026/27

Four legal strategies to escape the 62% effective marginal rate in the £100,000-£125,140 personal-allowance taper. Pension sacrifice, Gift Aid, salary deferral and bonus sacrifice fully worked.

The £100,000-£125,140 band is the highest-marginal-rate slice in UK personal tax - 62% before any HICBC, student loan or pension AA taper stacks on top. Four legal moves let you escape it.

Why £100k bites so hard

Above £100,000 adjusted net income (ANI), the £12,570 Personal Allowance is withdrawn at £1 for every £2 earned. Fully tapered at £125,140 - the standard 45% additional rate cuts in.

Effective marginal rate in the band:

40% Income Tax on the marginal £
2% National Insurance (above Upper Earnings Limit, only the 2% rate applies)
Plus 40% tax on the £0.50 of Personal Allowance lost
= 62% combined marginal rate

For parents this gets worse. Tax-Free Childcare (worth up to £2,000/child/year) + 30 free childcare hours are both withdrawn entirely at £100,000 ANI - no taper, hard cliff. Crossing £100k by £1 can cost £4,000+ in lost childcare support for a family with two pre-school children.

HMRC projects ~1.5 million UK taxpayers sit in this band in 2026/27 - up from ~750,000 in 2017/18 thanks to frozen thresholds since 2010.

The four escape moves

1. Salary sacrifice into pension

The headline move. Each £1 sacrificed reduces gross pay → reduces ANI → preserves PA + childcare benefits.

Example: £115,000 earner sacrifices £15,000 into pension.

Pre-sacrifice ANI: £115,000 (£12,570 PA × (1 - (£115k - £100k)/£25,140) = £5,070 of PA retained = £7,500 lost)
Post-sacrifice ANI: £100,000 → full £12,570 PA restored
Net cost: ~£5,700 (62% relief on £15,000)
Pension build: £15,000 added to pot
Plus: TFC + 30 free childcare hours restored (worth up to £4,000+/yr for parents)

Best move for those whose employer offers salary sacrifice (most UK workplace schemes do). Employer also saves 15% employer NI - some schemes split this back into your pension.

2. Relief-at-source personal pension contribution

For those without salary sacrifice (older schemes, self-employed). Pay £8,000 net into a personal pension; the provider claims £2,000 basic-rate relief; you claim the additional 25% higher-rate + the PA-taper restoration via Self Assessment.

Net economics close to salary sacrifice but with a worse cash-flow profile (you pay now, claim back at year end). Also misses the employer NI saving.

3. Charitable donation via Gift Aid

Gift Aid donations reduce ANI £-for-£ after grossing up by 25%. £8,000 cash donation = £10,000 grossed-up = £10,000 ANI reduction. You also get higher-rate relief on the difference.

Net cost on a £10,000 gross donation in the 62% band: £3,800 (62% relief).

This is the move for charitably inclined high earners or those whose pension is already at AA limit. The CT saving compounds if you have charitable causes you would support anyway.

4. Bonus / one-off sacrifice into pension

A discretionary bonus is the cleanest sacrifice target - it's typically not contractual and the employer is often happy to redirect it directly to pension.

If you'd otherwise sit at £100k base + £30k bonus = £130k total:

Sacrifice the entire £30k bonus into pension
ANI drops back to £100,000
Net cost: ~£11,400 (62% relief on £30k)
Pension build: £30,000 + employer NI saving (~£4,500 if returned by employer)

The £60,000 Annual Allowance applies - check carry-forward from the previous 3 tax years if planning a large lump sacrifice.

Stacking the moves

You can combine multiple. A £130,000 earner with childcare obligations might:

Sacrifice 10% (£13,000) into pension via salary sacrifice
Direct half their £20,000 discretionary bonus into pension
Make a £4,000 Gift Aid donation to a children's charity

Total ANI reduction: £27,000. Final ANI: £103,000 - mostly out of taper, retaining most of PA + childcare benefits.

What to watch out for

Annual Allowance £60,000 - combined employee + employer pension contribution capped. Above triggers an AA charge equal to your marginal rate (62% in this band). Carry-forward from previous 3 years can extend this.
Tapered Annual Allowance - kicks in only when BOTH (a) "threshold income" exceeds £200,000 AND (b) "adjusted income" exceeds £260,000. Reduces AA to as low as £10,000 for very high earners. Pension sacrifice can keep threshold income below £200,000 and avoid the taper entirely.
Mortgage affordability - lenders use gross salary not post-sacrifice. Sacrifice aggressively only if you're not about to apply for a mortgage.
Life cover / DIS - often a multiple of gross salary. Sacrifice can reduce these benefits.
State Pension qualifying years - sacrificing below the Lower Earnings Limit (£6,708/yr 2026/27 = £129/wk) breaks NI qualifying year credit. Above LEL is fine.

Tools for the move

Salary sacrifice optimiser - finds your sweet-spot %
What-if simulator - models the take-home delta of any sacrifice change
Tax trap visualiser - shows the 62% curve graphically
Salary calculator - main engine, configures sacrifice + region

Not financial advice. Pension decisions should consider long-term retirement income needs not just current-year tax efficiency.

Frequently asked questions

Why is the effective marginal rate 62% above £100,000?: Above £100,000 adjusted net income, you lose £1 of the £12,570 Personal Allowance for every £2 earned (fully tapered at £125,140). That extra PA loss is taxed at 40%, giving an effective marginal rate of 40% IT + 2% NI + (£1 PA × 40%) = 62%. The next £25,140 of income is taxed at 62% combined.
Does pension sacrifice reduce adjusted net income?: Yes - salary sacrifice pension contributions reduce gross pay before Income Tax is calculated. Personal pension contributions through relief-at-source also reduce adjusted net income for the £100,000 calculation (see HMRC Helpsheet HS345 Adjusted net income).
Does Gift Aid reduce adjusted net income?: Yes - donations made under Gift Aid are deducted from adjusted net income for the £100k taper calculation. The donation is grossed-up by the Gift Aid 25% bonus first, then deducted (so £100 donation = £125 gross-up = £125 deduction).
Is the £100k trap real or just optics?: Real and material. Plus Tax-Free Childcare and 30 free childcare hours are withdrawn at £100,000 - for parents the effective rate spikes past 100% on small slices of income (a £1,000 pay rise can produce zero net gain after losing TFC).