SEIS Tax Relief for UK Startups: The Founder’s Guide

Raising your first round of outside money is one of the hardest things a UK founder will do. The Seed Enterprise Investment Scheme, or SEIS, exists to make that first raise easier. It gives private investors generous tax breaks for backing very early stage companies, which makes your startup a more attractive investment. In short, SEIS is a UK scheme that rewards investors for backing very young companies. As a founder, the process is: confirm your company qualifies, get Advance Assurance from HMRC before you raise, issue ordinary shares, trade for at least four months, then file form SEIS1 so investors receive SEIS3 certificates and claim 50 percent income tax relief.

Since April 2023 a company can raise up to 250,000 pounds under SEIS, and each investor can invest up to 200,000 pounds per tax year. Get the process right and SEIS can transform a difficult fundraise into a compelling offer. Get it wrong and the relief can be lost entirely.

Most articles about SEIS are written for investors. This one is written for you, the founder.

What Is SEIS and Why Should Founders Care?

SEIS is a government scheme designed to encourage investment in young, high risk companies. It does this by giving investors tax relief on the money they put in, which makes your startup a more attractive investment in three ways. It widens your investor pool, because many angels only back SEIS qualifying rounds. It speeds up decisions, because the relief cushions the downside. And it shapes your fundraising strategy, because the scheme’s limits dictate how you plan your seed round and the rounds after it. If you are still deciding whether to raise equity at all, our parent guide on business loans vs personal loans explains when borrowing beats giving away shares, and when equity suits a high growth startup.

How SEIS Works From the Company’s Side

Think of SEIS as a three stage process: qualify, raise, comply.

Stage 1: Qualify. Before you take any money, you check that your company meets HMRC’s conditions and you apply for Advance Assurance. This is HMRC’s non binding confirmation that your company and your planned share issue look like they will qualify.

Stage 2: Raise. You issue ordinary shares to investors and take their money. The shares must meet strict conditions, and the investors must meet conditions of their own.

Stage 3: Comply. After you have traded for at least four months, you submit a compliance statement (form SEIS1) to HMRC. HMRC then authorises you to issue SEIS3 certificates to your investors, which they use to claim their tax relief through Self Assessment.

At no point does the company itself receive a tax break. The relief goes to the investor. Your job as founder is to build and protect the conditions that let your investors claim it.

What Your Investors Get (And Why It Helps You Raise)

You do not need to become a tax adviser, but you need to speak the language of the relief when you pitch. Here is what SEIS offers investors under the rules current for 2026.

• 50 percent income tax relief. An investor can cut their income tax bill by half of what they invest, up to 200,000 pounds per tax year. Unused relief can be carried back one year.
• Capital gains tax exemption. Gains are tax free if the investor holds the shares for at least three years.
• Capital gains reinvestment relief. Half of a capital gain is exempt if reinvested into SEIS shares.
• Loss relief. If the company fails, the investor can offset the loss (minus income tax relief already received) against income or capital gains tax.

Put together, an investor’s true at risk capital can be far lower than the cheque they write. That is your pitch. For a deeper look at how tax planning fits into running a small company, see our guide to tax planning strategies for small business owners.

How to Pitch SEIS to Angel Investors

Knowing the reliefs is not enough. You need to translate them into numbers an angel can feel. Most founders under sell SEIS because they describe it in abstract terms. The founders who close fastest put a simple worked example in their pitch deck.

A worked example: a 50,000 pound investment

Imagine an angel who pays income tax at 45 percent and invests 50,000 pounds in your SEIS round.

So a 50,000 pound cheque can cost the investor just 13,750 pounds if everything goes wrong, while a successful exit is free of capital gains tax after three years. Walk an angel through this maths and the conversation changes.

What to put in your deck

• One line on SEIS status: “Advance Assurance received from HMRC” with the date. This is the single most reassuring line for an angel.
• The worked example above, tailored to your round size.
• The round structure: amount raising under SEIS, share price, and confirmation that the shares are ordinary shares with no preferential rights.
• Your SEIS3 timetable: when investors can expect their certificates.

Does Your Company Qualify for SEIS?

This is the first gate, and it is entirely your responsibility. Check each condition before you promise investors an SEIS round. Figures reflect the rules in force since April 2023, current for the 2026 tax year.

The core company conditions

• UK based and unquoted. Your company must be established in the UK and must not be listed on a recognised stock exchange. It must not be controlled by another company.
• Young. The company must be less than three years old when the shares are issued, measured from the date it started trading. This limit was extended from two years in April 2023.
• Small. Gross assets must be no more than 350,000 pounds immediately before the investment (raised from 200,000 pounds in April 2023). The company must have fewer than 25 full time equivalent employees.
• Independent. The company must not be a subsidiary or under the control of another company at the time of the share issue.
• A qualifying trade. The company must carry on, or intend to carry on, a qualifying trade. Many activities are excluded, including financial services, property development and dealing, hotels, nursing homes, and most asset backed businesses. Check the excluded activities list carefully if your business touches finance, property or hospitality.
• SEIS first. Your company must not have received investment under the Enterprise Investment Scheme (EIS) or from a Venture Capital Trust (VCT) before. SEIS is strictly for first money in. You can raise EIS after SEIS, but never the other way round.
• New shares, new money. The money raised must be spent on the qualifying trade, generally within three years of the share issue.

The 250,000 pound lifetime cap

Since April 2023, a company can raise a total of 250,000 pounds under SEIS across its lifetime (previously 150,000 pounds). This is a hard cap. Once you have raised 250,000 pounds of SEIS money, every later round must use EIS or another route.

Qualifying Shares and Qualifying Investors

Even if your company qualifies, the relief fails if the shares or the investors do not meet the rules.

The shares must be ordinary, full risk shares

• They must be new ordinary shares with no preferential rights to dividends or assets on a winding up.
• They must carry no right of redemption (the investor cannot demand their money back).
• There must be no arrangement to protect the investor from risk, such as a guaranteed buyback or a linked loan.

In practice this means a straightforward ordinary share issue. Complex preference structures can break SEIS, so keep the seed round simple and take advice before adding special share rights.

The investors must be independent and unconnected

• Each investor must be a UK taxpayer to benefit from income tax relief.
• An investor (together with their associates) must not hold more than 30 percent of the company’s shares, voting rights or loan capital.
• Most employees cannot invest, although directors can. This is a deliberate feature: it lets founder directors and non executive directors put money in alongside angels.
• The investor must hold the shares for at least three years. If they sell early, the relief is clawed back.
• The investment must not be linked to a loan back to the investor.

As a founder, your practical job is to check the 30 percent rule for every investor and to make sure no side agreements create a protected return.

Advance Assurance: How to Apply Before You Raise

Advance Assurance is HMRC’s advance opinion that your company and your proposed share issue should qualify for SEIS. It is not legally binding and it does not guarantee relief, but in practice almost no serious angel will invest without it. Here is how to apply.

What to prepare

You apply to HMRC’s Small Company Enterprise Centre. Include your company details and Unique Taxpayer Reference, a description of the trade and how the money will be used, the amount you plan to raise and the proposed share structure, your latest accounts or projections with a business plan, details of any previous investment, and draft investment documents such as the term sheet if available.

The application process

1. Draft the application. Many founders use an accountant or SEIS specialist. You can also apply yourself using HMRC’s guidance and the Advance Assurance form.
2. Submit to HMRC. Send it to the Small Company Enterprise Centre, following the current instructions on GOV.UK.
3. Answer follow up questions. HMRC often asks about the trade, the use of funds or the company structure. Respond promptly and precisely.
4. Receive the assurance letter. If satisfied, HMRC confirms that on the information provided, the company and the share issue would appear to qualify.

Timelines: apply early

HMRC aims to process Advance Assurance applications within weeks rather than months, but complex cases take longer and HMRC may ask several rounds of questions. Apply as soon as your round is taking shape, ideally at least two to three months before you need to close. Investors will ask for the assurance letter during due diligence, so having it early removes friction.

One common question: can you raise without Advance Assurance? Legally, yes. Commercially, it is very difficult, because investors bear the risk that the relief fails. Treat Advance Assurance as effectively mandatory for a first SEIS round.

Common reasons HMRC asks follow up questions

Most delays come from a handful of predictable issues.

• Vague description of the trade. Describe what the company does, who pays for it, and how the SEIS money will be spent on it. A holding company or a bare idea will draw questions.
• Unclear use of funds. Break the raise into concrete spending: product development, hires, marketing. “Working capital” on its own is weak.
• Possible excluded activities. If your business is near property, finance, hospitality or asset backed services, address the exclusion head on with evidence your trade falls outside it.
• Previous funding. Disclose all grants, loans and earlier share issues. HMRC checks whether earlier EIS or VCT money blocks SEIS.

SEIS and Your Cap Table: Valuation, Dilution and Deal Terms

SEIS shapes the commercial terms of your round, not just the tax paperwork. Founders who understand this negotiate better and avoid surprises.

Keep the round SEIS simple

SEIS shares must be ordinary shares with no preferential rights and no redemption rights. That rules out several instruments founders sometimes reach for.

• No preference shares with priority returns. A 1x liquidation preference, common in venture rounds, is incompatible with SEIS. Your seed round should be plain ordinary shares.
• No convertible loan notes in the SEIS round. SEIS relief applies to shares, not debt. Keep any bridge financing separate from the SEIS share issue.
• No buyback or put arrangements. Any agreement letting the investor sell shares back to the company undermines the full risk requirement.

Simple is also faster. A clean ordinary share round with a standard subscription agreement closes quicker and costs less in legal fees.

Valuation and the 30 percent rule

Because no investor (with associates) may hold more than 30 percent after the round, your valuation and round size interact. On a 1 million pound post money valuation, a single investor group cannot hold more than 300,000 pounds of shares. In a 250,000 pound SEIS round that is rarely binding, but it bites when family members invest together and their holdings are aggregated.

Dilution across the SEIS to EIS journey

Model at least two rounds before you set the SEIS valuation. A typical path dilutes founders 15 to 25 percent in the SEIS round, then again in the EIS round. Give away too much too cheaply now and you reach the EIS round with a demoralised cap table and little room to incentivise the team. Price the SEIS round fairly and keep an option pool in mind for key hires.

Raising the Money and the SEIS3 Compliance Process

Once you have Advance Assurance, you can close the round. The compliance work that protects your investors’ relief happens after the money lands.

Issuing the shares

Issue new ordinary shares to each investor and take payment in full. Keep clear records of the amount each investor paid and the date. Update your statutory books, file the allotment with Companies House, and issue share certificates. Keep the total within the 250,000 pound lifetime cap, and keep copies of every subscription agreement and board minute. HMRC can ask for them years later.

The SEIS3 process step by step

1. Trade for at least four months. You cannot submit the compliance statement until the company has carried on the qualifying trade for at least four months after the share issue.
2. Submit form SEIS1. This compliance statement confirms the company, the trade and the share issue met the SEIS conditions.
3. HMRC authorises SEIS3 certificates. If satisfied, HMRC sends you blank SEIS3 certificates or authorisation to issue them.
4. Issue SEIS3 certificates to investors. Complete one per investor. The investor needs it to claim relief.
5. Investors claim through Self Assessment. Each investor claims income tax relief on their tax return, with the option to carry relief back one year.

Your record keeping duties

Keep everything: the Advance Assurance letter, subscription agreements, board minutes, share certificates, bank statements showing receipt of funds, and evidence of how the money was spent. If HMRC opens an enquiry into an investor’s claim, the company is the first place it looks. Organised finances start with the basics in our guides to creating a business budget and reading and analysing financial statements.

Sequencing SEIS Then EIS Across Funding Rounds

Most startups that use SEIS will later raise under EIS. The two schemes are designed to work in sequence, but the ordering rules are strict.

The golden rule: SEIS must come first

A company can raise SEIS and then EIS, but never EIS and then SEIS. If you take even a pound of EIS or VCT money first, SEIS is closed to you forever. If there is any chance you will want SEIS money, take the SEIS round first.

A typical sequencing plan

Planning the handover

• Watch the SEIS cap. Once the 250,000 pound allowance is used, structure the next round for EIS from the start: fresh Advance Assurance for EIS, EIS compliant shares, and EIS1 compliance instead of SEIS1.
• Mind the age limits. EIS has a seven year window from first commercial sale (ten for knowledge intensive companies). Do not burn time between rounds if you plan to rely on EIS later.
• Keep the cap table clean. The 30 percent connected person test applies under EIS too, and later investors will diligence your SEIS round. Sloppy SEIS paperwork can spook EIS investors.
• Model the dilution. Each round dilutes founders and early angels. Build a simple round by round model before you agree valuations, and keep a cash buffer so you are never forced to raise on bad terms. Our guides to cash flow management for small business and building an emergency fund for your business cover the cash discipline that keeps you in control between rounds.

Common Pitfalls That Disqualify a SEIS Round

These are the mistakes that cost founders their investors’ relief. Most are avoidable with planning.

1. Taking EIS or VCT money first. Even a small earlier EIS investment permanently blocks SEIS. Sequence matters more than size.
2. Issuing shares before checking the trade qualifies. Excluded activities are the silent killer. If your trade touches property, finance or hospitality, get advice before promising SEIS.
3. Breaching the 30 percent rule. An investor plus associates must not exceed 30 percent of shares, votes or loan capital. Family members investing together can breach this without realising.
4. Creating protected returns. Buyback agreements, guaranteed exits, preference shares with priority returns, or loans linked to the investment all break the full risk requirement.
5. Missing the spending rules. SEIS money must be spent on the qualifying trade, generally within three years. Parking it indefinitely is a problem.
6. Letting gross assets creep over 350,000 pounds. Check the asset test immediately before each share issue. A grant or asset purchase mid round can tip you over.
7. Failing the four month trading test. You cannot file SEIS1 until the company has traded for four months after the issue. Founders who raise before launch can get stuck waiting.
8. Sloppy SEIS3 administration. Late or incorrect SEIS1 filings, missing certificates, or lost records leave investors unable to claim. Treat compliance as part of the fundraise.
9. Assuming Advance Assurance is a guarantee. It is an opinion based on the information you provided. If the facts change, for example the trade pivots into an excluded activity, tell HMRC.
10. Forgetting the three year hold. Investors must hold for three years or lose relief. Build this expectation into your investment documents.

SEIS vs EIS: Which Should Your Startup Use?

For most founders the answer is not either or, it is SEIS first, then EIS. But it helps to see the schemes side by side.

If you are brand new, tiny and raising your first external round, SEIS is almost certainly your scheme. If you have already raised SEIS, outgrown the caps, or taken EIS money before, EIS is your route. New to startup finance altogether? Start with our business finance for beginners UK guide.

Frequently Asked Questions

What is SEIS tax relief in simple terms?

SEIS is a UK scheme that gives tax breaks to people who invest in very young companies. Investors get 50 percent income tax relief on up to 200,000 pounds per year, tax free gains if they hold the shares for three years, and loss relief if the company fails. The relief goes to the investor, but founders use it as a fundraising tool.

How does a founder apply for SEIS?

The company applies for Advance Assurance from HMRC’s Small Company Enterprise Centre before raising, describing the trade, the funding need and the planned share issue. After Advance Assurance, the company issues shares, trades for at least four months, then submits form SEIS1. HMRC then authorises SEIS3 certificates for investors.

How long does SEIS Advance Assurance take?

HMRC aims to deal with applications within weeks, but complex cases take longer. Allow at least two to three months between applying and closing your round, and apply as soon as the round takes shape.

How much can my startup raise under SEIS?

Since April 2023, a company can raise up to 250,000 pounds under SEIS in its lifetime. Each investor can invest up to 200,000 pounds per tax year and claim 50 percent income tax relief. Once the 250,000 pound cap is reached, later rounds must use EIS or other funding.

Can directors invest under SEIS?

Yes. Unlike the general employee restriction, directors can invest in their own company’s SEIS round. Most other employees cannot. The 30 percent connected person limit still applies to directors and their associates.

Can we raise SEIS after taking EIS investment?

No. This is one of the strictest rules in the scheme. If your company has received EIS or VCT investment, it can never raise SEIS afterwards. Always take the SEIS round first if you plan to use both schemes.

What is an SEIS3 certificate?

The certificate HMRC authorises your company to issue to each investor after you file the SEIS1 compliance statement. Investors need it to claim SEIS income tax relief through Self Assessment. Without it, they cannot claim.

When can we submit the SEIS1 compliance statement?

After the company has carried on the qualifying trade for at least four months following the share issue. You cannot file it immediately after closing the round, so build this waiting period into your investor communications.

What trades are excluded from SEIS?

Excluded activities include financial services, property development and dealing, hotels and nursing homes, and several other mainly asset backed trades. If your business touches these areas, check the excluded activities list on GOV.UK and take advice before promising investors SEIS relief.

Can SEIS investors also claim loss relief?

Yes. If the shares become worthless, the investor can claim loss relief on the amount invested minus the income tax relief already received, offset against income tax or capital gains tax.

Conclusion

SEIS is one of the most founder friendly fundraising tools in the UK. It does not give your company money directly. It gives your investors a powerful reason to say yes, and it gives you a structured, credible process for your first round: check the qualifying conditions, secure Advance Assurance early, issue clean ordinary shares, trade for four months, file SEIS1, and issue SEIS3 certificates.

The founders who get the most from SEIS treat compliance as part of the fundraise from day one. They sequence SEIS before EIS, they watch the 250,000 pound cap and the 30 percent connected person rule, and they keep records that would survive an HMRC enquiry. Do that, and SEIS becomes more than a tax relief. It becomes a competitive advantage in every conversation with an angel investor.

Tax reliefs are complex and the rules can change, so consider professional advice before structuring your round. Then go and close it.

Disclaimer: This article is general information about UK tax reliefs as understood for the 2026 tax year, not tax advice. SEIS rules are detailed and fact specific. Consider consulting a qualified accountant or tax adviser before relying on them for your fundraise.