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How UK founders can use SEIS to fund, grow and exit their startup

Discover how UK founders can leverage the Seed Enterprise Investment Scheme (SEIS) to fund their business, accelerate growth and plan a smart exit. Learn eligibility, tax benefits and key strategies.

Sam Simpson
Published 28th October 2025

The Seed Enterprise Investment Scheme (SEIS) is one of the most powerful tools available to early-stage startups in the UK. Designed to attract investors with significant tax reliefs, it also offers founders a unique opportunity to invest in their own businesses and benefit from considerable tax benefits, making it a smarter, more tax-efficient way to fund their business growth. This article explores the benefits of SEIS, eligibility criteria for founders and businesses, and practical scenarios for maximising its impact.

Contents:

  1. What is SEIS and Why Should Founders Care?
  2. Key Benefits of SEIS for Founders
  3. What's the impact on founders of investing under SEIS?
  4. How Founders Can Invest Under SEIS
  5. Practical Scenarios for SEIS Eligibility
  6. Final Thoughts: Why SEIS Matters for Founders
  7. How we can help
  8. FAQs

What is SEIS and Why Should Founders Care?

Seed Enterprise Investment Scheme (SEIS), alongside the Enterprise Investment Scheme (EIS), incentivises investment in small and early-stage businesses by providing substantial tax reliefs to investors. For founders, these schemes offer a dual advantage: attracting investors and creating a pathway for founders to invest in their own businesses with significant tax benefits. SEIS is specifically designed for very early-stage businesses, typically those in their first three years. Because of the higher risks associated with these startups, SEIS offers more generous tax reliefs compared to EIS, making it a compelling option for both investors and founders.

Key Benefits of SEIS for Founders

For founders, SEIS is more than just a tax-saving mechanism - it’s an investment strategy that reduces risk while increasing potential rewards. The scheme offers 50% income tax relief on investments up to £200,000 per tax year, significantly lowering the upfront financial burden. Additionally, any profits made on SEIS shares sold after three years are exempt from Capital Gains Tax, and shares held for over two years are free from Inheritance Tax, providing strong long-term incentives. From April 2026 however, 50% of the value of business assets (including S/EIS shares) that exceed £1 million will not be taxed, and the remaining 50% will be subject to Inheritance Tax charged at 20%.

Loss relief is another major advantage. If the business does not succeed, founders can offset their investment losses against income tax or other capital gains, reducing the net risk of investing their own money into the company. This safety net makes SEIS investments particularly attractive for founders looking to balance the risks and rewards of entrepreneurship.

What's the impact on founders of investing under SEIS?

Let’s consider two founders, both investing £100,000 in their business. Founder A uses SEIS, while Founder B does not. They both exit for £20m. TODO - Uploaded image description

How Founders Can Invest Under SEIS

Eligibility Criteria

For the Business

  • Age: SEIS applies to companies that have been trading for less than three years.
  • Size: Must have fewer than 25 employees and gross assets under £350,000.
  • Location: The business must have a permanent UK establishment.
  • Qualifying Trade: Certain industries (e.g., finance, property development) are excluded.

See the HMRC guide on Criteria when applying for S/EIS

For the Founder

  • Ownership Limit: Founders (including connected parties like spouses or relatives) must own 30% or less of the company to qualify for SEIS tax relief.
  • Director Status: Founders must be directors rather than employees to claim relief. See the HMRC guide on Venture Capital Schemes
  • Investment Structure: Shares must be paid in full, in cash, at the time of issuance.

Practical Scenarios for SEIS Eligibility

It isn't universally possible for founders to make use of SEIS in their own company. Specifically, where a sole founder will own all shares, it will be impossible. There are however some common scenarios where SEIS for founders maybe a great fit by owning 30% or less, for example:

  • Multiple Founders: Four co-founders, each owning 25%, can qualify for SEIS during incorporation, potentially, by carefully investing in 'subscriber shares'.
  • Founders joining later: It maybe that initial founders can't make use of SEIS, but founders joining later can benefit from the scheme - again, subject to being below the 30% limit.
  • Asymmetric Shares: A sole founder can initially hold 100% of the shares. Further co-founders joining through SEIS investments can hold up to 30% each, though the original founder will forgo SEIS benefits.
  • Early Investor: For example, if three founders hold 30% each and an investor takes a 10% stake during incorporation.
  • Foreign Ownership: A foreign founder owning 50% does not affect SEIS eligibility for UK-based founders, provided that remaining UK co-founders hold 30% or less each.

TODO - Uploaded image description

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Final Thoughts: Why SEIS Matters for Founders

SEIS is more than just a tax incentive - it’s a game-changer for founders. By enabling founders to invest in their own businesses with substantial tax benefits, SEIS reduces the risks associated with entrepreneurship while maximising the rewards. With features like income tax relief, Capital Gains Tax exemptions, and loss relief, SEIS ensures that founders are better protected financially as they grow their businesses. Founders who use SEIS not only position themselves for greater long-term success but also attract outside investors who are drawn to the scheme’s robust benefits. On the other hand, those who choose not to use SEIS miss out on these advantages, potentially exposing themselves to higher financial risks and tax liabilities.

How we can help…

At FounderCatalyst, we understand the challenges founders face when navigating SEIS/EIS eligibility and compliance. Our new feature simplifies this process, ensuring that both you and your business meet all necessary criteria to qualify for these valuable tax benefits. From filing applications to managing documentation, we guide you every step of the way, allowing you to focus on growing your business. Let us help you unlock the full potential of SEIS— click here to learn more.

FAQs

1. But employees can't invest under SEIS?!

Employees cannot invest under SEIS, but directors can explicitly invest under SEIS - HMRC states:

"In order to qualify for SEIS, neither the investor nor any associates may be employees of the company or any qualifying subsidiary in period B unless they are also a director. An individual is not treated as employed by the company if they are a director of the company."

For more details, see the HMRC Venture Capital Schemes Manual.

2. Does the SEIS 30% rule make it impossible for founders to invest?

No, see the scenarios above: Practical Scenarios for SEIS Eligibility - though if you can't get an individual founders ownership below 30%, they won't be able to make use of SEIS.

3. How can founders structure their investments for maximum tax efficiency?

Founders typically invest via SEIS instead of making a director's loan. SEIS allows for significant tax benefits, such as up to 50% income tax relief and potential capital gains tax (CGT) savings.

Even small investments, such as £1,000, qualify, and the legislation does not mandate a minimum Pre-Money Valuation (PMV). Investing through SEIS could save millions in CGT compared to funding the early stage of the business via a directors loan, for example.

4. Does the "risk to capital" condition make founder investments difficult?

No, meeting the "risk to capital" condition is straightforward for most startups. While HMRC evaluates whether the investment supports genuine growth rather than tax avoidance, in practice, they rarely challenge SEIS investments made by directors. The Tax Tribunal has upheld the legitimacy of directors using SEIS.

For instance, there is no tax avoidance clause for the CGT relief in SEIS, as seen in cases like Oxbotica Limited v HMRC.

5. Can a founder qualify for SEIS benefits if they are already connected to the company?

Yes, founders can qualify for SEIS even if they are connected to the company already, unlike EIS which has stricter rules around how can invest.

For more clarity, the relevant clause in the legislation (ITA07/S257BA) ensures that founders investing in their own company remain eligible. Without this clause, directors would not be able to use SEIS, making the provision a clear intention of Parliament.

6. Can HMRC reject founder SEIS claims on grounds of tax avoidance?

While HMRC can theoretically reject SEIS claims if they believe the investment is for tax avoidance, they have repeatedly lost such challenges in Tax Tribunals. For example, in cases like Oxbotica Limited, HMRC's arguments were dismissed. The SEIS framework is explicitly designed to include founder investments.

7. Isn't this a lot of hassle and a little more expense?

If you can make use of Founder SEIS, then the process is a little more time consuming and may incur some additional costs, for example to move money into the business via an accountant or lawyers client account.

But, keep in mind that this hassle/cost could result in you saving millions in capital gains tax so, if you are optimistic that your startup will be a great success, it's probably worth a little pain up front. And if you aren't optimistic about your chances of success, you may want to rethink your plans in any event?

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