Volume 01 | SEIS education, policy notes and founder reading Get the weekly SEIS Briefing
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Plain-English SEIS reading for founders, investors and advisers.

SEIS Explained
Latest updates
What Is SEIS? A Plain-English Guide to the Seed Enterprise Investment Scheme· SEIS and EIS: Using Both Schemes in Sequence· SEIS Statistics 2026: What the HMRC Numbers Say· SEIS After the Latest Budget: What Changed and What Did Not· The SEIS Evidence Trail: Why Good Rounds Fail on Paper· How SEIS Tax Relief Works·
Startup founders in a modern office
The UK SEIS reading room

Understand SEIS before you invest, raise or advise.

SEIS (the Seed Enterprise Investment Scheme) is a UK government scheme that gives investors up to 50% income tax relief for backing very early-stage companies, and lets qualifying companies raise up to £250,000. This is a plain-English guide to how it works, who it’s for, and the point where general reading needs to become professional advice.

SEIS Explained 12 min read Updated reading route
Start with SEIS Explained Choose your reader track

Written and edited by the SEIS Investments desk · education only, not financial advice.

The essentials

SEIS at a glance

The Seed Enterprise Investment Scheme in plain numbers and plain answers. The essentials before you read on.

Figures verified against gov.uk (HMRC) · educational information, not advice
50%Income tax relief for investors
£250kMaximum a company can raise
£200kInvestor limit per tax year
Under 3 yrsCompany age cap · under 25 staff

What is SEIS?

SEIS (the Seed Enterprise Investment Scheme) is a UK government scheme that encourages people to invest in very early-stage companies by offering generous tax reliefs. It launched in 2012 and is run by HMRC.

How much tax relief does SEIS give?

Investors can claim 50% income tax relief on up to £200,000 invested per tax year, plus capital gains tax reliefs and loss relief if the company fails.

How much can a company raise under SEIS?

A qualifying company can raise up to £250,000 in total. It must generally be under three years old, with fewer than 25 employees and gross assets under £350,000. (Limits rose on 6 April 2023.)

What is the difference between SEIS and EIS?

Both are UK venture-capital tax-relief schemes for unquoted companies. SEIS targets the earliest, smallest companies and gives 50% income tax relief; EIS is for larger, later-stage companies and gives 30%.

Who is SEIS for?

Three groups: founders raising early funding, investors seeking tax-efficient exposure to start-ups, and the advisers and accountants who support them.

Is SEIS a safe investment?

No. Investing in early-stage companies is high-risk and many fail. The reliefs reduce the downside but don’t remove the risk. Everything here is education, not investment advice.

How do I claim SEIS tax relief?

You claim SEIS income tax relief through your Self Assessment tax return, using the SEIS3 certificate the company sends you after the shares are issued. Relief can be claimed in the year you invest, or carried back one year.

How long does SEIS advance assurance take?

Usually a few weeks, though it varies with HMRC workload and how complete the application is. It signals a company looks likely to qualify. It is not a guarantee, so founders should apply early and investors should still do their own checks.

Ready to go deeper? Start with the plain-English guide to how SEIS works, who it’s for and where the rules bite.

Start with SEIS Explained →
Interactive tool

Not sure where to start? Take the SEIS Compass.

A five-minute guided check that builds you a personal SEIS checklist, whether you are a founder preparing a first raise or an investor reviewing an opportunity.

Educational planning only. No advice, and nothing here is a recommendation.

SEIS explained

The reading shelf for anyone trying to understand SEIS properly.

Start with the plain-English basics and go as deep as you need, from first definitions through the rules, risk, claims and the SEIS vocabulary.

Founders working with documents in an office
Core explainer

What SEIS covers, what it does not cover and why the distinction matters.

Start here before moving into founder preparation, investor education or adviser reference.

Read the explainer
SEIS scheme data shown as charts on a laptop
Statistics

SEIS by the numbers, updated every year

The scheme in HMRC data, refreshed annually, with our read on what it shows.

See the numbers
Reader desks

Three routes into the same SEIS archive.

Pick the desk that matches the question: founders need sequence, investors need education and advisers need reference depth.

For founders

Founder Room

For teams planning a raise, preparing for assurance or trying to avoid avoidable SEIS errors.

Explore SEIS for founders
For investors

Investor Notes

Educational reading on reliefs, risks, due diligence and claiming, with no invest now language.

Explore SEIS for investors
For advisers

Adviser Library

Technical reading, client scenario notes and compliance-friendly material for accountants and advisers.

Explore SEIS for advisers
News and updates

Policy desk, HMRC reading notes and scheme watch.

Track official material, fiscal signals and guidance changes with context, clear sourcing and a visible advice boundary.

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Lead update

How to read official SEIS updates without losing the practical point.

Budget notes, HMRC guidance and scheme statistics can be useful, but readers need context, plain language and a clear reminder that published material is not personal advice.

Budget watch

What early stage finance teams should check when tax policy changes

A calm checklist for reading announcements, not a prediction or recommendation.

By Hannah Clarke · 15 Jul 2026

Read
HMRC guide

Advance assurance and evidence: how the process is usually discussed

What founders should organise before they speak to professional advisers.

By Hannah Clarke · 12 Jul 2026

Read
Scheme data

Using SEIS statistics carefully, what the numbers can and cannot show

A reading note for journalists, founders and ecosystem teams.

By Hannah Clarke · 9 Jul 2026

Read
Compliance

Why education content must stay away from investment promotion

A publishing note on advice boundaries, risk language and responsible CTAs.

By SEIS Investments desk · 7 Jul 2026

Read
Analysis and perspective

Our reading of the rules, and where they catch people out.

Plain analysis and worked examples from the SEIS Investments desk, showing how the scheme behaves in practice. We explain it, we do not promote it.

Contribute

Share your SEIS story

Raised under SEIS, invested through it, or advised on a round? We are gathering real experiences for future founder and investor features. If you are happy to share how it went, we would like to hear from you.

Tell us your experience
In depth

Longer reads that make the rules easier to follow.

Editorial features and worked examples from our desk on how the SEIS process actually plays out, written to explain rather than to promote.

A founder organising notes before a raise
Founder guide

Before the raise: getting your SEIS evidence trail in order

The questions, documents and timeline founders should sort out early.

By Sam Whitfield · 14 Jul 2026 · 7 min read

Read the guide
An adviser and a founder discussing advance assurance
Analysis

What founders often misunderstand about advance assurance

Where the process gets misread, and what assurance does and does not confirm.

By Sam Whitfield · 11 Jul 2026 · 8 min read

Read the analysis
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Investor guide

The questions behind a good SEIS due diligence checklist

Business risk, tax position, claims and why reliefs should not replace judgement.

By Ravi Menon · 8 Jul 2026 · 7 min read

Read the notes
Video desk

Curated SEIS videos for readers who want to watch first.

A curated YouTube watchlist for beginner explainers, assurance walkthroughs, investor relief education and adviser conversations.

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Founder

Get your SEIS or EIS advance assurance the easy way

A practical walkthrough of preparing HMRC advance-assurance material.

 A team reviewing SEIS information on screen
Investor

Smart investing with EIS & SEIS: how UK tax relief works

Reliefs, risk and the tax incentives, explained for investors.

 Colleagues discussing SEIS in a bright office
Adviser

Unlocking EIS & SEIS: tax relief and investor insights

An expert-led look at reliefs, funding and adviser context.

 People working through SEIS material on computers
Compare

Intro to SEIS & EIS for fundraising

How SEIS and EIS sit together from a fundraising angle.
Tools and checklists

Practical SEIS checklists and downloads.

Downloadable references for eligibility, assurance documents, investor questions and SEIS vocabulary.

✓

SEIS Compass

Fourteen honest questions for founders, twelve for investors, then a traffic-light readiness report, instantly.

Start the check
£

SEIS calculator

Relief, worst-case cost and CGT savings on your own numbers, instantly and privately.

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01

SEIS eligibility checklist

A founder-facing checklist to prepare questions before speaking to advisers.

Open
02

Advance assurance document list

A practical list of materials founders may need to organise.

Open
03

Investor due diligence questions

Prompts for education, risk review and professional advice conversations.

Open
04

SEIS glossary

A clean vocabulary page for assurance, reliefs, certificates and claims.

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Weekly SEIS Briefing

Your weekly edit of SEIS reading, updates and practical notes.

Explainers, government and HMRC reading notes, founder guidance, investor education, adviser reference and selected analysis.

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Responsible reading

SEIS Investments publishes educational content only. Articles are not tax advice, legal advice, financial advice or investment recommendations. Readers should seek professional advice before acting.

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