SEIS

TL;DR

UK tax-advantaged scheme giving angels up to 50% income-tax relief on up to £200k/yr invested into very early-stage UK companies.

The Seed Enterprise Investment Scheme (SEIS) is HMRC's flagship incentive for very-early-stage UK startups. Qualifying companies, under three years old, fewer than 25 employees, and under £350,000 in gross assets, can raise up to £250,000 of SEIS investment in their lifetime. Individual investors get 50% income-tax relief on the amount invested, capital-gains exemption on a future exit if held for three years, and loss relief if the investment fails.

In practice, founders apply for Advance Assurance from HMRC before raising, then issue SEIS-eligible shares (ordinary, not preference) and file SEIS1/SEIS3 forms so investors can claim relief. The scheme is so attractive that most UK angel cheques expect SEIS treatment as the default, companies that fail to qualify often see cheque sizes drop sharply.

Formula

Investor Relief = min(Investment, £200,000) × 50%

• Investment, Amount the individual subscribes for SEIS-eligible shares in the tax year (UK only)
• £200,000, Annual SEIS subscription cap per investor as of tax year 2024/25

Capital-gains exemption on the eventual exit is separate from the 50% income-tax relief and requires the shares to be held for at least three years.

Worked example

A London angel writes a £40,000 SEIS cheque into a fintech. They claim £20,000 back via income-tax relief (40k × 50%), pay £0 capital-gains tax on any exit if held 3+ years, and claim loss relief at their marginal rate if the company fails, capping their downside at roughly £14,000 against a 20 to 40× upside.

Common pitfalls

• Issuing preference shares or share classes with rights that disqualify the round.
• Burning the SEIS allowance early and locking yourself out of the bigger EIS pool.
• Spending raised funds before issuing shares, relief only attaches to shares paid up in cash.

When this shows up in a pitch deck

UK seed decks usually call out 'SEIS Advance Assurance secured' on the Use of Funds slide so angels know their cheques will qualify.

Related terms

• EIS, UK scheme offering investors 30% income-tax relief on up to £1m/yr (£2m if knowledge-intensive) in qualifying UK growth-stage companies.
• Advance Assurance, Non-binding HMRC pre-clearance that a UK company's planned share issue likely qualifies for SEIS or EIS, used to de-risk angel investment.
• ASA (Advance Subscription Agreement), UK SEIS/EIS-compatible alternative to a SAFE: cash paid up-front for shares issued at the next round, with a 6-month longstop to keep relief.
• SAFE, Y Combinator's Simple Agreement for Future Equity, a contract that gives an investor the right to equity in a future priced round, with no debt or interest.
• Pre-Seed, The earliest priced or convertible round, typically raised on an idea, prototype, or very early traction with $250K to $2M from angels and pre-seed funds.

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