The Seed Enterprise Investment Scheme (SEIS) is one of the most generous tax incentives available to UK investors in early-stage companies. If you are building a fledgling business and need equity finance, SEIS can make your startup far more attractive to friends, family, business angels and small investors on modest incomes. By offering significant income tax relief and other tax advantages, the scheme helps de-risk the investment and encourages people to back young companies they believe in.

For women founders and other underrepresented entrepreneurs, who still receive a minority of traditional venture investment, SEIS can open doors. It lets you turn customers, mentors and personal contacts into shareholders without requiring the large cheque sizes that private equity or venture capital typically demand.

Unlike a loan, SEIS investment is equity: investors buy shares in your company. In return, HMRC offers them a package of reliefs, provided both the company and the investor meet strict eligibility rules. Because the rules are detailed and minor infringements can disqualify an issue, it is worth checking the latest GOV.UK SEIS guidance or speaking to an accountant before you start fundraising.

What tax reliefs does SEIS offer investors?

For the 2024/25 tax year, SEIS investors can claim:

• Income tax relief of 50% on investments up to £200,000 per tax year. A £10,000 investment therefore reduces the investor’s income tax bill by £5,000.
• Capital Gains Tax (CGT) exemption on any gain made when SEIS shares are sold, provided the shares are held for at least three years and income tax relief was given.
• CGT reinvestment relief on up to 50% of a chargeable gain that is reinvested in SEIS shares. For 2024/25, gains of up to £200,000 can qualify, meaning up to £100,000 of the gain can be exempt from CGT.
• Loss relief if the company fails or the shares are sold at a loss. The loss is calculated after deducting the income tax relief already received, and can be set against income tax or capital gains. For an additional-rate taxpayer, this can recover up to a further 22.5% of the original stake, taking total relief to around three-quarters of the investment.
• Inheritance Tax relief on SEIS shares held for at least two years, provided the company still qualifies.

These reliefs make SEIS particularly appealing to small investors who want to support a startup while limiting their tax exposure. However, tax relief is not a guarantee of return: early-stage investment remains high risk and investors may lose some or all of their capital.

Is your startup eligible for SEIS?

The scheme is designed for very early-stage trading companies. From 6 April 2023, the government expanded the limits, and the current rules for 2024/25 include:

• Maximum raise: your company can raise up to £250,000 in total under SEIS. This was increased from £150,000.
• Company age: the company must not have been carrying on qualifying trade for more than three years when the shares are issued.
• Gross assets: the company must have gross assets of no more than £350,000 immediately before the share issue.
• Employees: the company must have fewer than 25 full-time equivalent employees at the time of issue.
• Independence: the company must not be controlled by another company, and it must not have previously raised money under the Enterprise Investment Scheme (EIS) or Venture Capital Trust (VCT) scheme.
• Permanent establishment: the company must have a permanent establishment in the UK.
• Use of funds: the money must be spent on a qualifying trade within three years of the share issue.

Most ordinary commercial trades qualify, but some activities such as property development, financial services, farming and running hotels are excluded. Shares must be new ordinary shares, issued for cash and fully paid up when they are issued. They must not carry preferential rights to dividends or assets on a winding up.

It is also worth noting that SEIS is more restrictive than the Enterprise Investment Scheme (EIS). Once your company has raised its £250,000 SEIS limit or outgrown the age, asset or employee limits, you may be able to move on to EIS for larger rounds. Planning your funding ladder from the start can help you make the most of both schemes.

How to use SEIS to attract small investors

Once you are confident your startup qualifies, make SEIS a central part of your fundraising story. Many small investors are unaware of the scheme, so a clear explanation can turn interest into commitment.

• Get HMRC advance assurance. Although not a guarantee, an advance assurance letter from HMRC confirms that, based on the information provided, the investment is likely to qualify for SEIS. This gives investors confidence and is a useful addition to your pitch deck.
• Create a one-page SEIS summary. Explain the 50% income tax relief, the three-year holding period and the risk of loss. Use plain English and avoid promising returns.
• Target your own network first. Friends and family are often the earliest backers. SEIS makes a £5,000 or £10,000 stake more affordable because the net cost after tax relief is much lower.
• Consider equity crowdfunding. Platforms that specialise in early-stage equity can pool dozens of small SEIS investors in a single funding round. Read our guide to crowdfunding to see whether it fits your business.
• Work with business angels and networks. Angels frequently use SEIS and EIS as part of their portfolio strategy. A startup with advance assurance and clean paperwork is far more likely to attract serious interest.

Be transparent about risks. SEIS shares are illiquid and the company may fail. Investors should only invest money they can afford to lose, even with the tax relief. Providing a balanced picture builds trust and helps you meet regulatory expectations around financial promotions.

Common pitfalls to avoid

Minor administrative errors are one of the most common reasons SEIS relief is refused. Make sure you:

• Apply for advance assurance before you start promoting the investment as SEIS-qualifying.
• Issue shares correctly and keep records of payment.
• Spend the funds on qualifying business activity within three years.
• Keep your company’s structure simple. Different classes of shares, complicated shareholder agreements or side letters can jeopardise SEIS eligibility. If you are unsure, get advice before you issue shares rather than trying to fix problems later.
• Do not issue shares to investors who are “connected” with the company under HMRC rules, such as employees or people holding more than 30% of the shares, unless an exemption applies.
• Submit your SEIS1 compliance statement to HMRC once you have spent at least 70% of the funds on qualifying business activity, so you can issue SEIS3 certificates and investors can claim their tax relief.

Next steps

SEIS can be a powerful tool for startups that need modest amounts of equity and want to widen their investor base beyond traditional lenders. By combining a compelling business plan with clear information about tax relief, you can encourage small investors to back your vision.

Start by reviewing the latest eligibility criteria on GOV.UK, then seek professional advice and apply for HMRC advance assurance before you open your funding round. With the right preparation, SEIS can help turn your network into shareholders and give your startup the capital it needs to grow.