SEIS Capital Gains Tax Reliefs Explained
The two CGT reliefs inside SEIS: reinvestment relief on the way in, disposal relief on the way out, with worked numbers.
In this article
SEIS CGT relief comes in two distinct forms and people persistently blur them. Reinvestment relief works on the way in: shelter half of an existing gain by reinvesting it. Disposal relief works on the way out: pay nothing on the SEIS shares themselves after three years. Different events, different rules, happily stackable. Here is each, with the arithmetic.
Reinvestment relief: the way in
Realise a chargeable gain, on property, shares, a business, and subscribe for SEIS shares in the same tax year, and you can exempt half of the amount reinvested, permanently. The mechanics:
- Match the year. The gain and the SEIS subscription must fall in the same tax year for this relief.
- Half, not all. The exemption is 50% of the matched amount, inside the £200,000 SEIS annual envelope.
- Exemption, not deferral. Unlike the EIS equivalent, the sheltered half never comes back into charge. This is the single most misunderstood line in the scheme.
- Claim it with the income tax relief, using the SEIS3, per the claiming guide.
Worked: you sell a rental flat, realising a £80,000 gain taxed at 24%. You subscribe £80,000 into SEIS companies the same year. £40,000 of gain is exempt, saving £9,600, and the subscription separately earns £40,000 of income tax relief. Combined benefit before the shares move an inch: £49,600.
Disposal relief: the way out
Hold the SEIS shares at least three years, with the income tax relief given and not withdrawn, and a sale at a profit is simply not a chargeable event. No CGT, no cap, no tapering, and no claim form; you return the disposal as exempt. Sell a £10,000 stake for £150,000 in year five and the £140,000 gain is yours entire. The condition to respect: lose the income tax relief, by early sale, connection or value received, and this exemption goes with it.
And if it goes the other way
CGT symmetry has a kind edge: a loss on SEIS shares is not wasted. It converts, net of the income tax relief you kept, into loss relief against income or gains, which is the third leg of the stool and covered in its own guide.
Planning notes advisers repeat
- Sequence sales and subscriptions inside one tax year when reinvestment relief is the goal; a gain in March and a subscription in May sit in different years and miss.
- Partial matching is allowed: reinvest £30,000 of a £100,000 gain and £15,000 is exempted. You choose the matched amount when claiming.
- Rates matter: the exemption is worth the CGT rate you would have paid, so residential gains benefit most at current rates.
- Keep both certificates and computations: the SEIS3 and your gain calculation travel together in any later enquiry.
SEIS CGT relief side by side: the two forms
| Reinvestment relief | Disposal relief | |
|---|---|---|
| When | Year you invest | When you sell, after 3 years |
| Applies to | A gain made elsewhere | The SEIS shares themselves |
| Amount | 50% of the matched gain | 100% of the share gain |
| Nature | Permanent exemption | Permanent exemption |
| Claim | Yes, with the SEIS3 | No claim; conditions must hold |
The timing traps
Reinvestment relief lives and dies by the tax year boundary. A gain realised in late March needs SEIS shares issued by 5 April to match; miss it and the pairing fails, whatever the paperwork says about intentions. Fund investors face the mirror image: subscriptions deployed across two tax years scatter the matching, so a gain in year one may find only part of its shelter. The fixes are unglamorous: sequence disposals and subscriptions with the calendar open, and ask any fund for its deployment schedule before relying on it, as the routes guide recommends.
The record pack that survives an enquiry
CGT claims age slowly; enquiries arrive late. Keep together: the SEIS3 for each subscription, your computation of the original gain with dates and proceeds, the matching election showing which slice you exempted, and, for the eventual disposal, the three-year evidence that the income tax relief survived intact. One folder per investment, assembled in the week the certificate arrives, converts a future enquiry from an excavation into an email.
Against the EIS treatment
The schemes diverge sharply here. EIS deferral parks a gain and hands the bill back on exit; SEIS reinvestment relief extinguishes half of it permanently. EIS disposal relief mirrors the SEIS exemption after three years, so the way out is similar; the way in is not. For an investor holding a fresh gain and choosing between the schemes, that difference alone can decide the order in which the money moves, and it is set out side by side in the comparison guide.
Common questions
Does SEIS defer or exempt capital gains?
Exempts. Reinvestment relief permanently exempts half the matched gain; the EIS scheme is the one that defers. Disposal relief exempts the whole gain on the SEIS shares after three years.
Do I pay CGT when I sell SEIS shares?
Not if you held them three years and your income tax relief was not withdrawn. Sell earlier and the gain is chargeable and the income tax relief clawed back.
Can I shelter a property gain with SEIS?
Yes. Reinvest the gain into SEIS shares in the same tax year and half the reinvested amount is exempt from CGT, within the £200,000 limit.
How SEIS CGT relief sits beside the annual exempt amount
Two smaller pieces of CGT machinery interact with the scheme and deserve a note. First, the annual exempt amount: everyone has a small yearly allowance of tax-free gains, and it applies before you reach for anything else. A modest gain may need no SEIS CGT relief at all, so run the allowance first and shelter only what is left. Second, ordering: reinvestment relief is claimed against a specific gain in a specific year, so where you have several gains, choose the one taxed at the highest effective rate.
Neither point changes the headline mechanics, but both change real outcomes. A £10,000 gain inside the allowance needs no shelter; a £100,000 property-adjacent gain taxed at the higher residential rate is the one to match against the round. The general rule holds: use the free allowance first, aim SEIS CGT relief at the most expensive gain, and let disposal relief handle the way out.
