SEIS vs EIS: What's the Difference and Which is Right for You? (2026)

SEIS and EIS are the UK's two main tax-advantaged venture investment schemes. Both offer substantial tax reliefs. Both involve illiquid, high-risk investments in unlisted companies. Both require self-certification as a high net worth or sophisticated investor for most routes to market.

The difference between them is fundamentally about company stage — and that difference has significant implications for risk, return, and which relief is relevant to your circumstances.

The fundamental difference — company stage

Everything flows from this. SEIS and EIS are designed for different stages of company life.

• SEIS is for seed-stage companies. Pre-revenue or very early revenue. Fewer than 25 employees. Less than three years from first commercial sale. These businesses are at the beginning of their commercial journey — they have a product concept, perhaps early customers, and they are using investment to prove the model. The 50% income tax relief reflects the higher risk at this stage.
• EIS covers a much wider range. Post-seed companies with a proven product. Growth-stage businesses scaling into new markets. Companies up to 250 employees and £15 million in gross assets that have been trading for up to seven years. Still private, still illiquid — but with more commercial evidence behind them.

Many companies use both. A startup raises SEIS at the seed stage, proves the model, then comes back for an EIS round as it scales. As an investor, you may be offered SEIS and EIS in the same company at different points in its history.

Tax relief — rate versus scale

• Income tax relief: SEIS wins on rate (50% vs 30%). EIS wins on scale — the £200,000 SEIS annual cap limits how much relief you can claim. EIS allows up to £1 million per year (£2 million for knowledge-intensive companies). For investors deploying significant capital, EIS is the more relevant vehicle.
• CGT exemption: Identical for both. Hold for three years, gains are tax-free.
• CGT deferral: EIS only. This is the big differentiator for investors with an existing capital gain. EIS allows you to invest a capital gain and defer the CGT until the EIS shares are sold — no cap on the size of gain that can be deferred. SEIS offers only a 50% reduction in CGT on a reinvested gain. If you have sold a property, exited a business, or disposed of a significant investment portfolio, EIS CGT deferral is uniquely powerful.
• Loss relief: SEIS is more protective. The higher 50% upfront relief means the net loss that needs covering is smaller. A 45% taxpayer's maximum effective loss after all reliefs: 27.5p in the pound for SEIS versus 38.5p for EIS.
• IHT: Both offer 100% Business Property Relief after two years.

Risk — both are high, SEIS is higher

SEIS investments are riskier than EIS investments. Not by scheme design but by company stage. A pre-revenue startup with no paying customers is more likely to fail than a growth-stage company with £2 million of revenue and a proven model.

The 50% income tax relief acknowledges this. The government is paying you more to take on more risk.

Neither scheme eliminates loss. For a 45% taxpayer:

• Worst-case effective loss on a failed SEIS investment: ~27.5p in the pound
• Worst-case effective loss on a failed EIS investment: ~38.5p in the pound

Both are real losses. Both are substantially better than losing money without any relief. But neither should be entered into lightly.

Which is right for you?

SEIS may be more relevant if:

• You want exposure to the earliest stage — pre-revenue, founders still proving the model
• You want the maximum income tax relief rate (50%)
• You are investing within the £200,000 annual cap
• You are comfortable with higher company-specific risk
• Your tax position benefits more from rate than scale

EIS may be more relevant if:

• You want to invest more than £200,000 per year in tax-advantaged venture
• You prefer companies with commercial traction already established
• You have a capital gain to defer — EIS CGT deferral is specifically designed for this and has no cap
• You have recently sold a property, business, or significant investment
• You want access to more developed companies with longer operating histories

Both may be relevant if:

• You have a meaningful annual investment budget and want diversification across stages
• You want to back companies from seed through to growth stage over time
• You are a business angel who invests across multiple rounds in the same company

Self-certification for both schemes

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 under the Financial Promotion Order 2005. This applies to both schemes. The certification is a regulatory requirement for financial promotions relating to unlisted securities — not an optional formality.