Seed Enterprise Investment Scheme (SEIS): 2026/27 UK Tax Guide

The Seed Enterprise Investment Scheme (SEIS) remains one of the most generous tax-advantaged venture capital schemes in the UK. Designed to encourage investment in early-stage, high-risk trading companies, SEIS offers unparalleled income tax and Capital Gains Tax (CGT) reliefs.

With the Finance Act 2025 significantly increasing the main rates of CGT to 18% and 24%, tax professionals advising high-net-worth clients in the 2026/27 tax year must intimately understand how to leverage SEIS to shelter capital and mitigate income tax liabilities.  This guide outlines the statutory framework, relief limits, and compliance mechanisms for the 2026/27 tax year.

Income Tax Relief: 50% at the Front End

Part 5A of the Income Tax Act 2007 (ITA 2007) governs SEIS income tax relief.  Section 257A grants individuals an entitlement to tax reductions when they subscribe for shares in companies carrying on new businesses.

The legislation fixes the SEIS relief rate at 50% of the qualifying investment.  For the 2026/27 tax year, the maximum annual investment limit upon which an individual can claim this 50% relief is £200,000.  Therefore, an investor can achieve a maximum income tax reduction of £100,000 per tax year.

The Carry-Back Facility

Section 257AB(5) of ITA 2007 provides a statutory “carry-back” facility.  Investors can elect to treat all or part of an SEIS share issue as if it had been issued in the preceding tax year, subject to the £200,000 annual limit applicable to that earlier year.

“If in the case of any issue of shares— (a)which are issued in the current tax year, and (b)in respect of the amount subscribed for which the individual is eligible for SEIS relief, the individual so claims, subsections (1) and (2) apply as if… the shares had been issued in the preceding tax year”.

When calculating the final tax liability, section 27 of ITA 2007 establishes a strict order for deducting reliefs.  The system deducts VCT relief first, followed by EIS relief, and then SEIS relief.

Capital Gains Tax (CGT) Reliefs

Beyond the 50% income tax reduction, SEIS delivers two distinct CGT advantages, governed by the Taxation of Chargeable Gains Act 1992 (TCGA 1992).

1. SEIS Disposal Relief (100% Exemption)

Section 150E of the TCGA 1992 completely exempts any gain arising on the disposal of SEIS shares from Capital Gains Tax, provided the investor holds the shares for at least three years from the date of issue.

Crucially, the investor must have successfully claimed SEIS income tax relief on those specific shares, and HMRC must not have withdrawn or reduced that relief.  If the investor’s overall tax liability was too low to utilise the income tax relief, they lose the corresponding CGT disposal exemption.  However, if the claim simply reduces the investor’s tax liability to nil, the CGT exemption remains intact.

2. SEIS Reinvestment Relief

Schedule 5BB to the TCGA 1992 allows investors to shelter unrelated capital gains by reinvesting the proceeds into SEIS shares.  Unlike EIS deferral relief, SEIS reinvestment relief permanently exempts 50% of the reinvested gain from CGT.

Because the maximum SEIS investment limit is £200,000 for the 2026/27 tax year, an investor can exempt a maximum chargeable gain of £100,000.

Company Eligibility and Thresholds

To qualify for SEIS, section 257AA of ITA 2007 demands that the risk-to-capital condition is met, the investor is a qualifying investor, and the issuing company is a qualifying company.

Following significant expansions to the scheme effective from 6 April 2023, the qualifying company limits remain at their elevated levels for the 2026/27 tax year:

Compliance Certificates: A Mandatory Prerequisite

Investors cannot simply claim SEIS relief upon making the investment. Section 257EB of ITA 2007 dictates that an investor is only entitled to make a claim once they have received a formal compliance certificate (form SEIS3) from the issuing company.

The First-tier Tribunal reinforced this strict administrative requirement in Legend of Golden Temple Limited & Ors v The Commissioners for HMRC.

“The investor is entitled to make a claim for SEIS relief in respect of the amount subscribed by the investor for the relevant shares if the investor has received from the issuing company a compliance certificate in respect of those shares.”

Under section 257EC, the company issues this certificate to confirm that all general scheme requirements are currently met and will continue to be met.  If a company breaches these conditions (for example, failing the qualifying business activity rules), HMRC will withhold or withdraw the authorisation to issue the compliance certificates, thereby extinguishing the investors’ tax reliefs.

Consider reviewing the specific mechanics of the risk-to-capital condition under section 257AAA of ITA 2007 to ensure any newly structured special purpose vehicles genuinely seek to grow and develop a long-term trade.