EIS Carry Back Relief: Election, Limits, and Filing Deadlines

EIS carry back relief lets you treat shares you subscribe for in the current tax year as though they had been issued in the previous one, so the 30% income tax relief reduces last year’s tax bill instead of this year’s. You can carry back up to £1 million of investment, or £2 million if at least £1 million of that goes into knowledge-intensive companies. The election is made on the EIS3 certificate the company sends you once HMRC has authorised it.

How the Election Works

When you subscribe for shares in a qualifying EIS company, you can elect to have some or all of those shares treated as if they were issued in the tax year immediately before the one they were actually issued in.¹ The key word is “preceding”: you can only go back one tax year, never further.

You do not have to carry back the entire investment. Split it however suits your tax position, claiming part of the relief in the year the shares were issued and carrying the rest back. The carried-back amount is then treated for all purposes as if the shares were issued in that earlier year, which means it counts against that year’s annual investment limit and reduces that year’s tax liability.²

One constraint catches people out. EIS relief can only reduce income tax you actually owe. It cannot take your bill below zero, and any unused relief cannot be carried forward to a future year.² So carry back is only useful to the extent last year’s tax liability can absorb the 30% relief on the amount you shift back.

The Annual Investment Limits

The general annual cap on EIS investment for income tax relief is £1 million. If your investment includes at least £1 million into knowledge-intensive companies, the cap doubles to £2 million. These are the numbers that also govern how much you can carry back, because the carried-back sum has to fit within the previous year’s annual limit, not just the current year’s.

If you already invested up to the £1 million limit in the previous tax year, you cannot use carry back to squeeze more relief into that year on top. The mechanism attributes the shares to the earlier year for every purpose, including that year’s limit.

The EIS3 Certificate Is the Gate

You cannot claim any EIS relief, carry back or otherwise, until you hold a valid EIS3 compliance certificate from the company. The company obtains authorisation from HMRC by filing a compliance statement, and HMRC will not process this until the company has been trading for at least four months (or has completed four months of qualifying R&D activity). Once approved, HMRC issues the company an EIS2 form containing a Unique Investment Reference number, which authorises the company to distribute individual EIS3 certificates to each investor.³

Your EIS3 shows the amount you invested, the date the shares were issued, the company name, and the Unique Investment Reference. These details go on your tax return exactly as they appear. The certificate also contains a claim form, typically on the back or second page, where you specify how much of the investment you want to treat as invested in the previous year. Enter the full amount or just a portion, depending on your tax position in each year.

The date of share issuance on the EIS3 is the anchor for every timing rule that follows, including the carry back window and the three-year holding period. When you actually transferred the money is irrelevant; what counts is when the shares were formally issued in your name.

In practice, the EIS3 is the bottleneck. Companies sometimes take months, occasionally over a year, to obtain HMRC authorisation and issue the certificates. Without the EIS3 in hand, the claim cannot go anywhere.

Filing the Carry Back Claim

If you hold the EIS3 in time to file your Self Assessment return for the year the shares were issued, include the carried-back amount in box 2 of the “Other tax reliefs” section on the additional information pages, and list details of each investment in the “Any other information” box on page TR 7. To exercise the carry back option specifically, complete the claim form within the EIS3 showing the amount you want treated as invested in the previous year, and submit it to HMRC.⁴

If you have already filed your return for the relevant year before the EIS3 arrived, you can still claim. Complete the claim form inside the certificate and send it directly to HMRC. Online filers can upload the completed form through the secure messaging service in their personal tax account.⁴

When HMRC accepts the claim, they recalculate your liability for the previous year and typically issue a refund by bank transfer or cheque if you overpaid. Expect several weeks, and longer during peak filing periods. You can track progress through your personal tax account.

Deadlines

The deadline for an EIS carry back claim depends on when the shares were issued. The standard self-assessment framework allows claims within four years of the end of the tax year to which the relief relates, but EIS-specific claims have their own rules. If you are close to the edge of any deadline, get professional advice rather than assume.

If a deadline slips, HMRC may accept a late submission where you had a “reasonable excuse” that genuinely prevented you from meeting the obligation. Examples include serious illness, a hospital stay, the death of a close relative shortly before the deadline, or a fire or flood that destroyed your records. Finding the process confusing, forgetting about the deadline, or not receiving a reminder from HMRC does not count.⁵

Carry Back and the Three-Year Holding Period

Carry back does not shift the three-year holding clock. You must hold the shares for at least three years from the date they were actually issued. Sell before then and HMRC will withdraw the income tax relief, wholly or partly depending on how many shares you dispose of, and any gain on the early sale also becomes chargeable to capital gains tax.⁶

So if shares are issued in July 2025 and you carry the relief back to 2024–25, you still cannot sell those shares until July 2028 without triggering a clawback. The relief attaches to the earlier year for tax accounting; the shares themselves remain 2025 shares for holding-period purposes. Transfers to a spouse or civil partner do not count as disposals.

Relief can also be reduced during the holding period if you receive value from the company or a connected person. “Receiving value” is broadly defined and includes the company repaying a loan to you, providing services below market rate, or buying an asset from you at an inflated price. You can reverse the effect by returning the full amount received; partial returns do not count.⁷

Who Can Claim

Only individuals can claim EIS income tax relief. Companies, trusts, and partnerships cannot. You need a UK income tax liability large enough to absorb the relief, and you must not be “connected” to the company. The connection test is strict: you cannot directly or indirectly hold more than 30% of the company’s shares, voting rights, or assets on a winding up, and you cannot be an employee, though paid directors can qualify under a specific business angel exception.⁸

The business angel route allows a remunerated director to keep relief if their only connection is the directorship, their pay and benefits are reasonable, and they had no prior involvement with the company or its trade before the shares were issued (as owner, director, or employee). Getting the sequence wrong, for example by joining as a director before the shares are issued in a way that creates a prior connection, removes the relief entirely.⁹