A founder once said to me: “Everyone likes the idea, but nobody wants to be the first person to invest”.

That sentence captures the problem of many early-stage businesses. The idea may be strong. The founder may be credible. The market may be attractive.

But at the beginning, everything still feels uncertain. The company may have limited trading history, incomplete revenues, no full team, and a product that still needs investment before it can scale.

That is exactly the moment when the Seed Enterprise Investment Scheme, usually called SEIS, can become extremely useful.

SEIS is a UK tax relief scheme designed to help very early-stage companies raise money by making the investment more attractive to individual investors. HMRC describes SEIS as a scheme intended to help small, early-stage companies raise equity finance by offering tax reliefs to individual investors who buy new shares in those companies.

In simple terms, SEIS does not remove the commercial risk of investing in a start-up. But it can reduce the investor’s tax cost of taking that risk.

Why SEIS matters for founders

For a founder, raising the first external money can be difficult.

Investors often like the business, but they hesitate. They know that early-stage companies can fail. They know that forecasts are uncertain. They also know that even good founders need time, capital and execution discipline before a business becomes valuable.

SEIS helps because it gives the investor a tax reason to take the risk earlier.

A qualifying investor can obtain Income Tax relief at 50% of the amount invested, subject to the relevant limits and conditions. For the 2025/26 tax year, HMRC’s SEIS helpsheet confirms that the maximum amount on which an investor can claim Income Tax relief is £200,000.

So, for example, if an investor subscribes £20,000 for qualifying SEIS shares, the potential Income Tax relief may be £10,000, assuming the investor has enough Income Tax liability and the conditions are met.

That changes the conversation.

The investor is still taking a genuine commercial risk. The company may still fail. But the tax relief can make the risk more acceptable.

Why investors ask about SEIS early

Experienced angel investors will often ask: “Do you have SEIS advance assurance?”

They ask this because SEIS is not just a tax benefit. It is also a sign that the company has prepared properly.

A founder who understands SEIS usually has a clearer view of the funding round, the cap table, the use of funds, the company’s eligibility, and the documentation investors will need.

That gives investors confidence.

For early-stage companies, confidence matters almost as much as the pitch itself. A good idea may open the door, but clean structuring helps the investor walk through it.

What the company can raise

A company can receive a maximum of £250,000 through SEIS. HMRC’s guidance also makes clear that the company must follow the scheme rules for at least three years after the investment is made; otherwise, tax relief may be withdrawn from investors.

That point is very important.

SEIS is not something to “add” to the business after the investment has already happened. It should be built into the fundraising process from the beginning.

If shares are issued incorrectly, if the wrong investor subscribes, if the money is used for the wrong purpose, or if the company breaches the rules afterwards, the investor’s relief can be at risk.

That can create a serious commercial problem for the founder.

The capital gains tax advantages

SEIS can also provide important Capital Gains Tax benefits.

HMRC’s helpsheet explains that SEIS includes two CGT reliefs: reinvestment relief and disposal relief. Reinvestment relief can allow part of a gain to be treated as exempt where the gain is reinvested in qualifying SEIS shares. Disposal relief can apply where SEIS shares are sold after being held for at least three years, provided the relevant conditions are met and the Income Tax relief has not been withdrawn.

In practical terms, this means SEIS can be attractive not only for investors with income tax exposure, but also for individuals who have recently sold an asset and are looking at reinvestment opportunities.

However, the tax tail should not wag the investment dog. SEIS can improve the risk/reward position, but it does not turn a weak business into a strong one.

Where founders often get it wrong

The most common mistake is treating SEIS as a marketing label.

Some founders put “SEIS eligible” in a pitch deck before anyone has properly checked whether the company actually qualifies. That is risky.

The company must satisfy detailed conditions. The investor must also satisfy conditions. The shares must be new shares. The money must be raised and used for a qualifying business activity. The timing must be right.

There are also restrictions on certain investors. HMRC’s guidance explains that an investor may not qualify if, for example, they are an employee of the company, or if they have a substantial interest in the company; a substantial interest broadly includes more than 30% of the company’s share capital, voting power, or assets on a winding-up.

This matters because early investors are often friends, family members, advisers, commercial contacts or people already involved in the business. Their relationship with the company needs to be checked before shares are issued.

Advance assurance is helpful, but not a guarantee

Advance assurance from HMRC can be very useful. It gives investors comfort that, based on the information provided, HMRC expects the investment to qualify.

But it is not a complete guarantee.

If the facts later change, or if the actual share issue is different from what was described, the relief may still be challenged. The same applies if the company breaches the rules during the three-year period after investment.

This is why the process needs discipline. A founder should not only obtain advance assurance, but also make sure the company continues to comply after the money has been raised.

A simple way to think about SEIS

SEIS is best understood as a bridge.

On one side, there is a founder with an early-stage business that needs capital.

On the other side, there is an investor who may like the opportunity but is concerned about risk.

SEIS helps build the bridge between them.

It does this by reducing the investor’s tax cost, improving the commercial attractiveness of the round, and giving the fundraising process a more professional structure.

But the bridge only works if it is built properly.

How Vectigalis Tax can help

SEIS can be extremely valuable, but it needs to be handled carefully from the start.

Vectigalis Tax can assist founders, investors and advisers with:

• checking whether the company is likely to qualify;
• reviewing investor eligibility;
• preparing the tax analysis for SEIS advance assurance;
• identifying potential issues before shares are issued;
• coordinating the SEIS position with the wider fundraising structure.

For tailored SEIS and early-stage investment tax advice, please contact Vectigalis Tax:

Website: www.vectigalistax.co.uk
Email: angelo@vectigalistax.co.uk

SEIS can help a strong early-stage company raise money more confidently. But it should be treated as a technical tax regime, not just as a line in a pitch deck.

This article is for general information only and should not be relied upon as a substitute for advice based on your specific facts and circumstances.