HMRC collected £22.2 billion in capital gains tax in the 2025/26 tax year — by far the largest CGT take on record, and 62% higher than the £13.7 billion collected the year before. It blew past the previous peak of roughly £16.9 billion set in 2022/23, and came in well above the Office for Budget Responsibility's own forecast of £20.3 billion.
If you sold a property, a business, a portfolio of shares or crypto in the last eighteen months, there's a reasonable chance you're one of the people behind that number — and a reasonable chance you're now looking at a tax bill you didn't fully plan for.
You'll be glad to know there are two, HMRC-recognised ways to address that bill and put the money to work instead. Reinvesting the gain into Enterprise Investment Scheme (EIS) or Seed Enterprise Investment Scheme (SEIS) qualifying companies. This article sets out why 2025/26 produced a record CGT year, how EIS deferral relief and SEIS reinvestment relief actually works, and what a sensible reinvestment looks like once the tax bill is out of the way.
Tax treatment depends on individual circumstances and may change. Seek advice from a qualified and regulated Independent Financial or Tax Adviser if unsure about your personal circumstances.
Three things collided to produce £22.2bn:
Higher rates. The Autumn Budget 2024 raised CGT rates on shares and other assets to align with residential property — 18% for basic-rate taxpayers and 24% for higher and additional-rate taxpayers, on gains above the annual exempt amount.
A frozen, shrinking allowance. The annual CGT exemption has been cut sharply in recent years and now sits at just £3,000 for 2025/26 — down from £12,300 as recently as 2022/23. Far more modest gains now attract tax at all.
Behavioural crystallisation. Several commentators, including tax specialists quoted in the trade press this spring, pointed to investors and business owners bringing forward disposals once the direction of travel on rates became clear — locking in gains before further changes, rather than after.
The result: gains from property sales, business disposals and investment portfolios that would previously have escaped tax altogether, or been taxed lightly, are now generating six-figure bills for a much wider group of people than in previous years. Self-assessment bills reflecting these record gains would have landed with taxpayers in January 2026 — and 2026/27 disposals are happening against the same rate and allowance backdrop right now.
Capital gains tax deferral relief is one of the least well-known reliefs in the EIS toolkit, and one of the most useful for anyone who has just sold a large asset.
The mechanic is simple: if you reinvest an amount equal to your taxable gain into EIS-qualifying shares — directly or through a fund — you can treat that gain as if it hasn't arisen, for as long as you continue to hold the EIS shares. If you do sell your shares, and the gain arises, it can be deferred again by acquiring more EIS eligible shares.
A few mechanics worth knowing:
The deferral window is four years wide. To defer a gain, the EIS shares you acquire must be issued in the period beginning one year before, and ending three years after, the date of the disposal. You can defer a gain realised up to one year before, or three years after, your EIS investment. A sale that completed last year can still be matched against an investment you make now.
There's no cap on the size of the gain you can defer. Unlike EIS income tax relief, which is capped at £2m of investment per tax year (£1m before Budget rules changed the balance), deferral relief has no upper limit.
It stacks with income tax relief. The same EIS investment that defers your gain also earns 30% income tax relief on the amount invested — for an additional-rate taxpayer, that combination can cut effective downside exposure to well under 40p per £1 invested, before any return on the investment itself.
It compounds into inheritance tax planning. Once EIS shares have been held for two years, they qualify for 100% Business Relief and fall outside your estate for inheritance tax purposes — provided the shares are still held upon death and the combined value of your Business Relief assets sits under the £2.5 million per-person allowance introduced on 6 April 2026 (above which relief steps down to 50%). A single reinvestment decision can therefore address a CGT bill today and an IHT position later.
None of this is exclusive to property. The same deferral route applies to gains on a business sale, a share portfolio, or cryptocurrency disposals — HMRC treats the gain the same way regardless of the underlying asset, provided it's a genuine chargeable gain.
EIS deferral relief postpones a gain. SEIS reinvestment relief does something different — it makes half of it disappear permanently.
Reinvest a chargeable gain into SEIS-qualifying shares and 50% of the amount reinvested is exempt from CGT outright, not deferred. Important: you must claim SEIS income tax relief on the same investment to qualify for capital gains reinvestment relief.
The numbers make the mechanic concrete. A higher-rate taxpayer reinvesting a £25,000 gain into SEIS-eligible companies saves £3,000 in CGT — 50% of the gain at the 24% rate — on top of £12,500 in SEIS income tax relief at 50%, one of the most generous combinations in the UK tax code.
Three things separate it from EIS deferral relief, and matter when deciding which to use:
It's an exemption, not a deferral. The saving is permanent — there's no future tax charge to plan around when you eventually sell.
It's capped. SEIS's £200,000 annual investment limit means the relief only ever applies to gains up to £100,000 (half of £200,000) reinvested in a tax year — a ceiling EIS deferral relief doesn't share.
It comes with a higher income tax relief rate. SEIS income tax relief runs at 50%, against EIS's 30%.
SEIS reinvestment relief does not enjoy the same four year window as EIS deferral relief. In most cases, the gain you wish to claim reinvestment relief against must have arisen in the same tax year for which you have claimed income tax relief on your SEIS shares. If you carry back your income tax relief to the prior tax year, you may claim reinvestment relief on those shares for that prior tax year.
If you're sitting on a gain larger than £100,000, you can use both reliefs in sequence. Use SEIS reinvestment relief to permanently shelter the first £100,000 of gain, then use EIS deferral relief on everything above it.
SyndicateRoom's Carbon13 SEIS Fund X is one live route into SEIS-qualifying shares for investors looking to use this relief before the tax year closes — a high-conviction portfolio of climate tech startups built through Carbon13's venture-building programme, offering the 50% SEIS income tax relief alongside 50% reinvestment relief, together with loss relief, inheritance tax relief and tax-free growth. Tax treatment depends on individual circumstances and may change. Seek advice from a qualified and regulated Independent Financial or Tax Adviser if unsure about your personal circumstances.
Property sellers. Second homes, buy-to-lets and inherited property sold above the Private Residence Relief threshold are squarely in scope — and property CGT rates, now aligned with other assets at 18%/24%, no longer offer the shelter they once did relative to shares.
Business owners. A trade sale or share disposal often produces the largest single gain an individual will ever realise. Business Asset Disposal Relief reduces the rate on the first £1 million of qualifying gains, but anything above that — or any gain that doesn't qualify for BADR — sits fully exposed, and fully eligible for deferral.
Investors and crypto holders. Gains crystallised on share portfolios or crypto disposals qualify on exactly the same terms. For crypto specifically, HMRC's share-pooling rules determine the gain, but the deferral mechanic itself is unchanged.
For EIS, the four-year reinvestment window is generous, but it isn't indefinite, and it runs from the date of disposal — not the date the tax bill lands. Anyone who sold a property, a business, or a substantial portfolio in the 2024/25 or 2025/26 tax years should treat this as a live, time-limited decision rather than something to revisit "at some point."
The practical next step is straightforward: identify the gain, confirm it falls within the one-year-before-to-three-years-after window, and reinvest an amount equal to the gain into an EIS-qualifying vehicle before that window closes.
Two live funds cover the ground this article has walked through.
Angel Academe EIS Fund 2 is raising up to £1.5m to build a portfolio of 6–10 high-growth, female-founded tech and health-tech companies, targeting a 3x return net of fees. It's a fit for EIS deferral relief on the same terms set out above — the reinvestment window, the income tax stacking, the inheritance tax planning — channelled into a fund built specifically to close the capital gap facing female founders, who currently receive a disproportionately small share of UK venture funding.
Carbon13 SEIS Fund X is the fund to pair with the SEIS reinvestment relief covered earlier in this article. It's raising an exclusive £1.2m to back 4–10 pre-seed climate tech companies through Carbon13's venture-builder programme, targeting a 3x return net of fees, with a minimum investment of £10,000. Alongside 50% SEIS income tax relief and 50% reinvestment relief, it carries loss relief, inheritance tax relief and tax-free growth — the same reliefs set out in the SEIS section above, in a fund built for investors specifically looking to permanently shelter the first slice of a large gain.
If you're sitting on a 2024/25 or 2025/26 gain and haven't yet used deferral or reinvestment relief, the sensible next step is a conversation with your adviser about which fund better fits your allocation — EIS deferral through Angel Academe, or SEIS reinvestment relief through Carbon13 — before your reinvestment window narrows further.
Find out more about Angel Academe EIS Fund 2 and Carbon13 SEIS Fund X below:
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