SEIS (Seed Enterprise Investment Scheme) is a UK government program that makes early startup investing more tax-efficient for qualifying individual investors.

How it works

Eligible investors receive income tax relief on investments into SEIS-qualifying companies, with additional potential benefits on gains and losses subject to current HMRC rules. Companies must meet criteria on age, gross assets, employee count, and trading activity — and cannot be listed or in excluded sectors.

Founders often seek advance assurance from HMRC before marketing a round so angels know the raise will qualify. SEIS sits alongside EIS (Enterprise Investment Scheme) for slightly later or larger raises; combined limits apply per company lifetime.

Investment must be in new shares, not secondaries from founders. Structuring and timing mistakes can disqualify the round.

Why it matters

• Founders: SEIS can unlock UK angel capital that would otherwise wait for lower-risk stages. Plan the round with accountants familiar with advance assurance timelines.
• Investors: Tax relief improves risk-adjusted returns but does not fix weak companies — diligence still drives outcomes.

Common mistake

Assuming all UK startup equity automatically qualifies — trading status, prior funding, and subsidiary structures frequently block SEIS.

Related ideas

• EIS (Enterprise Investment Scheme)
• UK angel and syndicate investing
• Advance assurance and HMRC compliance