- The sections at a glance
- Section E: valuing what left
- Section F: reliefs after April 2026
- How the exit rate is built, before the first anniversary
- Grossing up when the trust pays
- Assets that haven't been relevant property for the full time
- After a 10 year anniversary
- Deadline, interest and signing
- The verdict
- Frequently asked questions
IHT100c is the HMRC form trustees use to report the exit charge, or proportionate charge, when assets in a relevant property trust stop being relevant property, usually because they're paid out to a beneficiary. It records what left the trust, works out the trust's effective rate, scales it by the number of complete quarters, and the tax is due 6 months after the end of the month of the exit.
This guide follows the April 2026 form and HMRC's How to fill in form IHT100c, updated in September 2026, as of October 2026. For the wider family of event forms, see our IHT100 guide.
The sections at a glance
| Section | What it covers |
|---|---|
| A to C | The settlor, the person dealing with the event, and the trust, including its start date, IHT reference and UTR |
| D | Which supplementary schedules you need, D31 to D39 |
| E | Assets leaving the trust, in boxes E1 to E18 |
| F | Liabilities, exemptions and reliefs |
| G and H | Rate and tax, when the exit is before the first 10 year anniversary |
| I and J | Rate and tax, when the exit is after a 10 year anniversary |
| K, L and declaration | Repayment account, tax avoidance scheme details, and signatures |
You fill in G and H, or I and J, never both. HMRC's guide says to go straight to Section I if the event happened more than 10 years after the trust started.
Section E: valuing what left
Value each asset at open market value on the date of the event, rounded down to the nearest pound, with tax shown to the nearest penny. Each box holds a total: E2 is every bank and building society account, for example, and the detail goes in Additional information. Land goes in E1 or E15 with schedule D36, and shares in E7 to E12 with schedule D32.
Column B is for assets where the tax can be paid in annual instalments over 10 years. HMRC notes that from 6 April 2026, tax on any shares that qualify for Business Relief can go into instalments, listed or unlisted.
Section F: reliefs after April 2026
Only debts the trust owed on the date of the event go in F1. Professional fees for work after the event, or for dealing with it, are left out. From 6 April 2026, 100% Agricultural and Business Relief is capped by new relief allowances, with value above the allowance getting 50%, and shares on markets HMRC doesn't treat as listed get only 50%. HMRC sends you to IHTM25500 and the D37 and D38 notes to work out your allowance.
How the exit rate is built, before the first anniversary
Section G collects history: what the settlor put in, valued when it went in and without reliefs, property that later became relevant property, related trusts set up the same day, and the settlor's chargeable transfers, each valued on the date it was made. Same-day additions to another trust count if they increased its value by more than £5,000, as of October 2026. Box G15 takes the nil rate band at the date of the charge, which HMRC tells you to take from its rates and tables published with the IHT400.
- Add the relevant property the settlor put in (H1), property that became relevant property (H2), related trusts (H3) and same-day additions (H4), then take off the nil rate band available. If the band covers it all, the rate is nil.
- Multiply what's left by 20%.
- Divide that by the total and multiply by 100 to get a rate, then multiply by 30%.
- Multiply by the number of complete quarters from the trust's start to the exit, and divide by 40. That's the effective rate in box H12.
- Apply it to the value leaving the trust in Section F.
HMRC's guide says if the total nil rate band available is nil, the initial rate of Inheritance Tax will be 6%. The quarters fraction is why an exit soon after a trust starts costs much less than one just before its tenth birthday.
Grossing up when the trust pays
If the trustees pay the tax from assets that stay in the trust, the loss to the trust is bigger, so the rate is grossed up. The formula on the form is the H12 rate divided by 100 minus that rate, times 100. The result goes in box H14 and is used instead of H12.
Assets that haven't been relevant property for the full time
The rate is cut for property that joined the trust, or became relevant property, after it started. HMRC's worked example has a trust starting on 1 January 2010 and a distribution on 1 August 2014 of assets worth £160,000, as of October 2026. Of that, £100,000 was added on 1 February 2011 and £60,000 became relevant property on 1 November 2012. With a rate of 4.8% in H12, the reductions are £1,680 for the first slice over 14 quarters and £504 for the second over 7 quarters.
The guide gives extra step-by-step methods for boxes H18, H19, J18 and J19 where grossing applies, and a cap in boxes H21 and J21 that only matters if the trust held excluded property at 30 October 2024.
After a 10 year anniversary
Sections I and J follow the same pattern, but start from the value at the last 10 year anniversary, as shown on HMRC's assessment or your own working. For events on or after 6 April 2026, the I1 value shouldn't include any Agricultural or Business Relief claimed before. Quarters are counted from the last anniversary instead of the start.
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Deadline, interest and signing
Tax is due no later than 6 months after the end of the month of the event, and late tax carries daily interest worked out with HMRC's calculator. If you don't have an IHT reference yet, leave box C4 blank. Repayments go by Faster Payments to an account in the names of everyone who signed, or one you nominate in Section K.
HMRC accepts IHT100 forms without a wet signature, as long as every trustee's details are on the declaration page. An agent or trustee adds HMRC's exact confirmation wording to the Additional information section.
The verdict
IHT100c is mostly arithmetic, but the arithmetic depends on history: the settlor's earlier gifts, related trusts, and when each asset became relevant property. Gather that before you open the form, pick G and H or I and J by the trust's age, and diarize 6 months from the end of the month of the payout.
The trust anniversary charge return guide covers a different form for readers who prefer to file it themselves.
Frequently asked questions
What is IHT100c used for?
To tell HMRC about an exit charge, also called a proportionate charge, when assets in a relevant property trust stop being relevant property.
When is the tax on an IHT100c due?
No later than 6 months after the end of the month in which the exit happened. Interest runs daily after that.
What is the maximum exit charge rate?
HMRC's guide says if no nil rate band is available, the initial rate is 6%, which is then scaled by the quarters the property has been in the trust.
Do I need to sign the IHT100c by hand?
No. HMRC accepts IHT100 forms without a wet signature if every trustee's details are on the declaration page.
What is grossing up on IHT100c?
If trustees pay the tax from assets left in the trust, the effective rate is grossed up: the rate divided by 100 minus the rate, times 100.
