EIS income tax relief lets you cut your UK income tax bill by 30% of whatever you put into qualifying shares, on up to £1,000,000 of investment a year. Invest £50,000 in an eligible company and, assuming you owe at least that much tax, you knock £15,000 off your bill. That is the entire headline - and the bit almost everyone gets slightly wrong is what the 30% is a percentage of, and when it actually shows up.
It is a tax reducer, not a deduction from your income. A £6,000 relief takes £6,000 straight off the tax you owe - it is not £6,000 knocked off your taxable salary, which would be worth far less. That distinction is where most of the confusion lives, so we will start there and build out.
The 30% comes off your tax bill, pound for pound - not off your income.
What does the 30% actually attach to?
The relief is 30% of the amount you subscribe for new shares - the cash you hand the company for its stock. Put in £20,000, the potential relief is £6,000. Put in £100,000, it is £30,000. Simple multiplication, with two important fences around it.
First, there is an annual limit. You can claim relief on up to £1,000,000 of EIS investment per tax year. That ceiling lifts to £2,000,000 if at least £1m of your total goes into knowledge-intensive companies - broadly, the research-and-development-heavy firms HMRC treats as higher-cost to build. Below those numbers, the maths is just 30% of what you invested.
Second, and this is the one that catches people: the relief can only wipe out tax you actually owe. It is non-repayable. If your 2026/27 income tax liability is £8,000 and your EIS relief comes to £12,000, you reduce the bill to nil and the extra £4,000 of relief does not arrive as a cheque. It is potential value with nothing to bite on. Which is exactly why carry-back exists.
How does carry-back work?
You can elect to treat an EIS investment as though you made it in the previous tax year and set the 30% against that year's income tax instead - up to that earlier year's annual limit, and only to the extent you had not already used it on other EIS shares. Nothing else moves; the shares were still issued when they were issued. You are simply pointing the relief at the year where the tax sits.
Two situations make this genuinely useful. You invest in March, near the end of the tax year, but your big tax bill landed in the year just gone - carry it back. Or your current-year liability is too small to absorb the full relief, while last year's was larger - again, carry back the slice that would otherwise be wasted. It is a one-year reach only; you cannot carry the relief forward.
A worked example
Say you put £40,000 into an EIS-qualifying startup in this tax year. The relief on offer is 30% of £40,000, or £12,000. Suppose your income tax liability this year is only £7,000. You use £7,000 of the relief to clear that bill, then carry back the remaining £5,000 of relief to last year, where you owed more than enough to absorb it. The full £12,000 lands - just split across two years. Get the same wrong, leave it all in the current year, and £5,000 of it evaporates.
What strings are attached to keeping the relief?
The 30% is conditional, and HMRC can take it back. Three conditions decide whether you keep it.
Hold the shares for three years
You must hold EIS shares for at least three years from the date of issue (or from when the company starts trading, if that is later). Sell inside that window and the income tax relief is clawed back. In practice the money is usually locked up far longer anyway - there is rarely a ready buyer for unquoted startup shares - but three years is the firm legal floor on the relief.
You have to be the right kind of investor
The relief is for outside investors putting capital at risk, not insiders. Broadly you cannot be an employee of the company (certain director arrangements aside), and your holding with associates cannot pass 30% of the company. And you need to be a UK taxpayer with a real liability - the 30% has nothing to reduce if you pay little or no UK income tax, so the relief is simply lost even though you still carry every penny of the risk.
The company has to qualify
This is the condition most outside your control, and where claims most often come unstuck. The business must be a young, unquoted company carrying on a qualifying trade. Under current HMRC rules it generally needs fewer than 250 full-time-equivalent employees, no more than £30 million in gross assets before the share issue (and not more than £35 million immediately after), and must take the investment within seven years of its first commercial sale. There are also annual and lifetime caps on how much a company can raise across the venture-capital schemes, with more generous limits for knowledge-intensive companies. These company-side figures were revised in April 2026, so confirm the current numbers on gov.uk's EIS guidance for companies rather than taking any of them on trust.
Your protection here is advance assurance - the non-binding nod a company can get from HMRC before the round, confirming the business looks EIS-eligible. Ask to see it. And note the trap: the rules can be breached after you invest. If the company drifts into a non-qualifying activity within three years, your relief can vanish through no fault of your own.
How do you actually claim the relief?
The process is mercifully simpler than the eligibility maze. After your shares are issued and the company has traded for the required period, it sends you an EIS3 certificate (or a unique investment reference for online claims). That document is your evidence the investment qualified.
You then claim through your Self Assessment tax return for the relevant year - or by writing to HMRC - entering the details from the certificate and electing any carry-back you want. No certificate, no claim. Companies are sometimes slow to issue EIS3s, so chase yours; the relief is real only once the paperwork is in hand. HMRC sets out the steps in its tax relief for investors guidance.
Where does this sit next to SEIS and VCT?
EIS is the middle child of a three-scheme family, and the income tax relief is the cleanest way to tell them apart.
- SEIS: 50% income tax relief on up to £200,000 a year, for the very earliest companies. Higher relief because the risk is even higher. Three-year hold, carry-back to the previous year.
- EIS: 30% relief on up to £1,000,000 a year (or £2m with knowledge-intensive investment), for slightly later, larger companies. Three-year hold, carry-back to the previous year.
- VCT (Venture Capital Trust): 20% relief on up to £200,000 a year, but a longer five-year hold, tax-free dividends, no capital gains tax on gains - and, unlike EIS, no loss relief.
A single company often raises a first slug under SEIS, then turns to EIS as it grows - so an angel can end up holding both, claiming 50% on the seed shares and 30% on the EIS tranche. For the wider EIS picture beyond the income tax line - capital gains deferral, tax-free growth, loss relief - see our full guide to the Enterprise Investment Scheme.
The honest bit
The 30% is generous because the underlying bet is harsh. The relief lowers your entry cost; it does nothing to improve the company. A depressing number of people have backed a flimsy business purely for the tax break and discovered that 30% off the price of a total loss is still, unmistakably, a loss. The relief belongs in the maths after you have decided the company stacks up on its own merits - never as the reason you back it.
To be plain: this is general editorial information, not financial or investment advice. The rules shift, your circumstances are your own, and the figures here can date. Before making any EIS investment, take advice from an FCA-regulated adviser and confirm the current position with gov.uk.
Frequently asked questions
How much EIS income tax relief can you claim?
EIS gives income tax relief worth 30% of the amount you invest in qualifying shares, on up to £1,000,000 of investment per tax year. That limit rises to £2,000,000 a year if at least £1,000,000 of it goes into knowledge-intensive companies. The relief reduces the income tax you owe; it is capped at the tax you actually have to pay, and it cannot create a refund beyond that.
Can EIS income tax relief be carried back to the previous tax year?
Yes. You can treat all or part of an EIS investment as though it were made in the previous tax year and claim the 30% relief against that year's income tax instead, subject to the annual limit for that earlier year. This carry-back is useful if you had a larger tax bill the year before, or invested late in the current year.
Do you need to be a UK taxpayer to claim EIS income tax relief?
Broadly, yes. EIS income tax relief only has value if you have a UK income tax liability to set it against. If you pay little or no UK income tax, the 30% has nothing to reduce, so the relief is wasted even though you still carry the investment risk.
What happens to EIS income tax relief if you sell the shares early?
If you sell EIS shares within three years of issue, or the company breaches the qualifying rules inside that window, HMRC can withdraw or reduce the income tax relief you claimed. You would then have to repay the benefit. The three-year minimum hold is a condition of keeping the relief, not just a guideline.
How do you actually claim EIS income tax relief?
Once the company has issued your shares and traded for the required time, it sends you an EIS3 certificate (or a unique investment reference for online claims). You use that to claim the 30% relief through your Self Assessment tax return for the relevant year, or by writing to HMRC. Without the certificate you cannot claim. This is general information, not financial advice.