How to fill in SA108 — reporting a capital gain on an estate or inherited asset
Form SA108 is the capital gains summary attached to HMRC's Self Assessment return (SA100) — where a chargeable gain on property, shares, cryptoassets or other investments gets declared for the tax year.
For an estate or a beneficiary, the gain almost always starts from a death: the acquisition cost resets to the market value at the date of death, so it's the growth after that date being taxed, not everything the deceased ever gained.
This walkthrough covers who actually files it, the two separate deadlines that trip people up, the residential property section most estates need, and what has to be enclosed alongside the boxes.
✓ Official source checked 23 August 2026 · GOV.UK last revised this form 13 May 2026SA108 on GOV.UK ↗
Free
United Kingdom·Informational, not legal or financial advice·Official source: GOV.UK
✓Official form · always current
This is the same official SA108 file HM Revenue & Customs publishes on GOV.UK — the link below fetches the current version live from GOV.UK the moment you click it, so it can never go out of date.
Current version: April 2026 · confirmed on GOV.UK 23 August 2026
This walkthrough takes SA108 field by field, for the two situations this site's readers actually hit. The base cost is the value at the date of death, not what the deceased paid for it — and a UK residential property sale usually needs its own 60-day report and payment first, with SA108 only reconciling that figure afterwards.
The thing most people get wrong
SA108 boxes 9 and 10 only reconcile a UK residential property gain that has already been reported and paid through the separate 60-day UK Property CGT service — they are not an alternative to it.
An estate that sells a house at a gain and waits for the year-end return to report it has missed a filing with its own penalty regime, one that starts well before SA108 is due at all.
The form, in summary
Valoren
SA108·4 pages·92 fields guided
With Valoren40 minutes
Without Valoren2–3 hours
pulling every disposal, working out the date-of-death base cost, and matching any UK property sale back to its 60-day filing
Deadline
31 Oct / 31 JanSA100 dates — but a UK property sale needs its own 60-day report first
Who Files
The sellerbeneficiary personally, or the estate via its own return
SA108 is the capital gains summary attached to the main Self Assessment return (SA100). It's where a chargeable gain — most often on a house, shares, or other investments — gets declared for the tax year.
For this site's audience, that gain almost always traces back to a death: either the estate itself sold an asset during administration, or a beneficiary later sold something they inherited. Either way, TCGA 1992 s.62 sets the acquisition cost at the market value on the date of death — not whatever the deceased originally paid for it, however long ago that was.
The boxes on SA108 are a summary only. The form itself states you must also enclose your computations — the working-out for each gain or loss, including valuations — as well as filling in the boxes; the notes repeat this.
You only need SA108 at all if total disposal proceeds for the year were more than £50,000, or chargeable gains before losses were more than the £3,000 annual exempt amount (2025–26), or you're bringing in a gain from an earlier year, or you want to claim a loss or make a claim or election.
·Who Files — Most directly: an individual — including a beneficiary who has sold an asset they inherited — filing their own SA100. Their base cost for that asset is the probate value under TCGA 1992 s.62(4), not the deceased's original purchase price, and any gain is measured from there.
An estate itself can also realise a chargeable gain during administration — typically selling a house or shares before distributing the proceeds — and personal representatives are liable for any CGT due on it. That liability is reported through the estate's own Trust and Estate Tax Return rather than a personal SA100; this walkthrough hasn't independently confirmed the exact form/box reference the current Trust and Estate return uses for capital gains, so check the live SA900 series on gov.uk before assuming SA108 itself is what an estate files. What's certain either way: SA108 is never about the personal representative's own income from acting as executor — only about a chargeable gain someone (the estate, or a beneficiary) actually realised.
·4 pages · 92 fields guided
·Draws from your Estate File — Financial Accounts, Legal Instruments
Section01
§11
Section 1
Before you start — who files this, and the value that changes everything
SA108 only applies once a threshold is crossed, and the base cost for anything connected to a death is never what the deceased originally paid.
01
When you need it at all
Total disposal proceeds over £50,000, or chargeable gains before losses over the £3,000 annual exempt amount (2025–26), or a gain from an earlier year taxable now, or you want to claim a loss or make a claim or election.
If none of those apply, there's nothing to file.
02
The date-of-death base cost
Under TCGA 1992 s.62, personal representatives are deemed to acquire the deceased's assets at market value on the date of death — wiping out whatever gain built up during the deceased's lifetime.
A beneficiary who later receives an asset from the estate takes it at that same value, with no gain realised on the transfer itself; their own gain, if any, is measured from there when they eventually sell.
03
Who actually files
An individual — including a beneficiary selling something they inherited — files SA108 with their own SA100. Where the estate itself realises the gain during administration, that's reported through the estate's own Trust and Estate return rather than a personal SA100; check the current gov.uk guidance for the exact form reference in that case.
04
The boxes are a summary, not the whole submission
The form itself says you must enclose your computations — the working for each gain or loss, including any valuations used — as well as filling in the boxes. Submitting the boxes alone is incomplete.
SA108 only applies once a threshold is crossed, and the base cost for anything connected to a death is never what the deceased originally paid.
HM Revenue & Customs (HMRC) · SA108❦
Section02
§22
Section 2
Two separate deadlines — don't let the year-end date lull you
SA108 follows the SA100 calendar. A UK residential property sale usually doesn't wait that long.
01
The SA100/SA108 deadline
31 October after the tax year end for a paper return, 31 January for an online one — SA108 has no separate date of its own.
02
The 60-day property deadline is different, and earlier
If the disposal is of UK residential property and there's CGT to pay, HMRC's UK Property CGT service needs its own report and a payment on account within 60 days of completion — not exchange.
This is a completely separate filing, with its own penalty regime, and it's very often due long before the year-end return is anywhere near ready.
03
How SA108 reconciles it afterwards
Box 9 is the total gain or loss on UK residential property already reported via the 60-day service; box 10 is the tax on that gain already paid. SA108 folds the earlier figure into the full year's return — it doesn't ask you to report the sale again from scratch, and it doesn't substitute for the 60-day filing if that hasn't happened yet.
SA108 follows the SA100 calendar. A UK residential property sale usually doesn't wait that long.
HM Revenue & Customs (HMRC) · SA108❦
Section03
§33
Section 3
The residential property section — the one most estates need
Boxes 3–13C cover UK residential property and carried interest together. Carried interest is a specialist fund-manager provision and won't apply to an ordinary estate; the property boxes usually will.
01
Gains before losses — box 6
The gain on UK residential property disposals for the year, before any losses are set against it.
02
The reconciliation boxes — 9 and 10
As above: the gain and tax already accounted for via the separate 60-day property return, folded into this year's total.
03
New for 2025–26 — boxes 6.1 and 13C
Amounts claimed under the foreign income and gains (FIG) regime that replaced the old non-dom remittance basis. Unlikely to feature in a straightforward UK estate, but check if the deceased or estate had a non-UK residence element.
Boxes 3–13C cover UK residential property and carried interest together. Carried interest is a specialist fund-manager provision and won't apply to an ordinary estate; the property boxes usually will.
HM Revenue & Customs (HMRC) · SA108❦
Section04
§44
Section 4
Everything else the form covers, briefly
SA108 has sections most estates will never touch. Worth knowing they exist, in case one applies to the specific assets involved.
01
Cryptoassets — boxes 13.1–13.8
Its own section since a 2023–24 redesign — relevant if the deceased or the estate held cryptoassets that were later disposed of.
02
Other property, assets and gains — boxes 14–22
Business Asset Disposal Relief claims, non-residential land and buildings, and personal chattels sold for more than £6,000 — box 18 itself is explicitly not in use.
03
Listed and unlisted shares — boxes 23–44
Quoted shares and securities in one section; unlisted shares — including EIS/SEIS-specific boxes for lifetime limits and share loss relief — in another.
04
Non-resident CGT and other specialist sections — boxes 51 onward
Non-resident Capital Gains Tax on UK land or property, and a narrow section for excluded indexed securities and QAHC share repurchases — unlikely to feature in an ordinary UK estate, but present if a specific holding calls for them.
SA108 has sections most estates will never touch. Worth knowing they exist, in case one applies to the specific assets involved.
HM Revenue & Customs (HMRC) · SA108❦
Section05
§55
Section 5
Losses, the personal representatives' allowance, and the final boxes
The closing sections carry the allowances and adjustments that decide how much of the gain is actually taxable.
01
Losses brought forward and carried forward — boxes 45–50.1
Where earlier years' losses reduce this year's gain, and where an unused loss carries forward to a future year.
02
The personal representatives' annual exempt amount
Under TCGA 1992 s.1K, personal representatives get the annual tax-free allowance for the tax year of death and the two tax years that follow — three tax years in total.
An administration that runs past that window loses the allowance for any later disposal, which can turn a marginal gain into a fully taxable one if a property sale is delayed.
03
Flagging an estimate — box 53
Tick this if any figure used is an estimate or a valuation rather than a confirmed sale price — for example, where a formal valuation stands in for an open-market sale.
04
Anything else — box 54
Free text for explaining a claim or election, or any other detail HMRC needs to make sense of the figures.
The closing sections carry the allowances and adjustments that decide how much of the gain is actually taxable.
HM Revenue & Customs (HMRC) · SA108❦
Section06
§66
Section 6
Before you submit
Two habits catch most of the errors this form produces.
01
Watch the box numbering
Box numbers on SA108 are not sequential — gaps and decimals (6.1, 13.1–13.8, 17.0–17.4, 52EG, 52QG) reflect years of additions bolted onto an older structure. Check the actual box label on the current form rather than assuming a number two apart from one you've just filled in is the next one.
02
Confirm the 60-day filing happened first
If any of the disposals were UK residential property with CGT due, check that the 60-day report and payment on account were actually made — and use those figures, not a re-worked estimate, in boxes 9 and 10.
03
Enclose the computations
Attach the working for every gain or loss reported, including how any valuation was reached — the boxes alone aren't treated as a complete submission.
Two habits catch most of the errors this form produces.
HM Revenue & Customs (HMRC) · SA108❦
Many people file SA108 themselves — that is what this walkthrough is for. If the situation behind it has stopped being simple — beyond what a careful person can safely do alone — Signum, Valoren’s own specialist desk, can take it on, and we say so plainly: it starts with a free intake, and if you do not need us, we will tell you. Prefer an independent adviser? STEP and the Chartered Institute of Taxation both keep public member directories, and neither pays Valoren a referral fee.
FAQ
SA108 questions, answered.
SA108 is the capital gains supplement to the main SA100 Self Assessment return. It's where a chargeable gain on property, shares, cryptoassets or other investments gets declared for the tax year.
The market value at the date of death — not whatever the person who died originally paid for it. That's the effect of TCGA 1992 s.62: personal representatives are deemed to acquire estate assets at their date-of-death value, and a beneficiary takes an asset from the estate at that same value with no gain on the transfer itself.
If it's UK residential property and there's Capital Gains Tax to pay, yes — HMRC's UK Property CGT service needs a report and payment on account within 60 days of completion, separately from and well before the year-end SA108. Boxes 9 and 10 on SA108 then reconcile that figure back into the full return; they don't replace the 60-day filing.
Only if total disposal proceeds for the year were more than £50,000, or chargeable gains before losses were more than the annual exempt amount (£3,000 for 2025–26), or you're bringing forward a gain taxable this year, or you want to claim a loss or make a claim or election.
The form itself says you must enclose your computations — the working-out behind each gain or loss, including valuations — as well as filling in the boxes. The boxes are a summary; HMRC still wants to see how you got there.
Personal representatives get the annual exempt amount for the tax year of death and the two tax years that follow (TCGA 1992 s.1K) — so an estate administration running longer than that loses the allowance entirely, which matters if a property sale is delayed into year four or later.
SA108 attaches to a personal SA100. Where the estate itself — rather than a beneficiary personally — realises the gain, that's reported through the estate's own Trust and Estate Tax Return; check the current SA900-series guidance on gov.uk for the exact form reference, since this walkthrough hasn't independently confirmed it.
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Where this fits
SA108 is one form. The file behind it is the rest.
Every SA108 figure for an estate or inherited asset starts from the date-of-death value HMRC already accepted on the IHT400/IHT411 valuation — that's the base cost the gain is measured against.
The Legal Instruments record holds those original probate figures; the Financial Accounts record holds the sale price, costs, and dates the disposal itself needs.