SEIS vs EIS: Which is Right for Your Investment?

SEIS and EIS are the UK's two main tax-advantaged venture investment schemes. Both offer generous tax reliefs to investors who back British companies. Both require you to take on real risk — these are illiquid, high-risk investments in unlisted companies. But they are designed for different stages of company and different types of investor opportunity, and the differences between them matter.

This guide sets out the key differences clearly so you can decide which is more appropriate for you — or whether a combination of both makes sense.

The fundamental difference: company stage

The most important distinction between SEIS and EIS is the stage of company each scheme is designed for.

SEIS is for very early-stage companies — typically pre-revenue or with very limited revenue, fewer than 25 employees, and less than three years from their first commercial sale. These are seed-stage businesses: they have an idea, perhaps a prototype, and they are using the investment to prove the concept and find early customers. The government offers the higher 50% income tax relief to compensate for the higher risk at this stage.

EIS covers a much wider range of companies — from post-seed companies with a proven product to growth-stage businesses scaling into new markets. The company can have up to 250 employees, £15 million in gross assets, and can have been trading for up to seven years. These are still private, illiquid companies, but they have more commercial traction than typical SEIS-stage investments.

Many companies do both: they raise SEIS at the very beginning, then return to their investor base (and new investors) for an EIS round once they have demonstrated the business model works. As an investor, you may be offered both SEIS and EIS in the same company at different points in its life.

Tax relief: SEIS wins on rate, EIS wins on scale

SEIS offers 50% income tax relief. EIS offers 30%. SEIS is the better rate — but SEIS caps at £200,000 per year, while EIS allows up to £1 million (or £2 million for knowledge-intensive companies). For investors deploying significant capital, EIS provides access to much larger investment opportunities.

The CGT exemption on gains is the same for both: hold for three years and profits are tax-free. The CGT deferral relief is available only through EIS, not SEIS (though SEIS offers a 50% reduction in CGT on a reinvested gain). IHT Business Relief applies to both.

Risk: SEIS is higher, relief is higher

SEIS investments are categorically riskier than EIS investments — not because the scheme is riskier in design, but because the underlying companies are earlier stage. A seed-stage company with no revenue is objectively more likely to fail than a growth-stage company with a proven model and paying customers. The 50% income tax relief reflects this: the government is compensating investors for taking on more risk.

Neither scheme eliminates the risk of loss. With SEIS, after all tax reliefs, the worst-case loss for a 45% taxpayer is approximately 27.5p in the pound. With EIS, it is approximately 38.5p in the pound. Both are real financial losses — the reliefs mitigate but do not eliminate them.

Which scheme is right for you?

Choose SEIS if:

• You want exposure to the earliest stage of company building
• You want the maximum income tax relief (50%)
• You are investing smaller amounts (up to £200,000 per year)
• You are comfortable with higher risk in exchange for higher potential returns and higher relief
• You want to back founders at the very beginning — before the product is fully proven

Choose EIS if:

• You want to invest more than £200,000 per year in tax-advantaged venture
• You prefer companies with some commercial traction already established
• You have a capital gain you want to defer — EIS CGT deferral is uniquely powerful for this
• You want access to larger, more developed companies with longer operating histories

Consider both if:

• You have a meaningful annual tax-advantaged investment budget and want to diversify across stages
• You are building a portfolio of venture investments and want exposure from seed through to growth stage

A note on self-certification

To access most SEIS and EIS investment opportunities, you will need to self-certify as either a High Net Worth Individual or a Sophisticated Investor. This is a regulatory requirement for financial promotions relating to unlisted securities. Both schemes require this — the process is straightforward and covered in our guide to investor self-certification.