SEIS Advance Assurance Explained: How UK Startups Can Make Angel Investment More Attractive

Raising a first angel round is difficult.

Investors are being asked to put money into a company that may have:

• little revenue;
• limited operating history;
• an unfinished product;
• a small team;
• and a significant risk of failure.

The UK Seed Enterprise Investment Scheme — SEIS — is designed to encourage investment into exactly this type of early-stage business.

For qualifying investments, SEIS can provide individual investors with significant UK tax relief.

That can make a qualifying startup considerably more attractive to UK angel investors.

But there is an important practical problem:

How does an investor know that the company is likely to qualify for SEIS before investing?

That is where SEIS Advance Assurance comes in.

A startup can apply to HMRC before issuing the relevant shares and ask HMRC whether the proposed investment is likely to meet certain requirements of the scheme.

This guide explains how SEIS works, what Advance Assurance actually means, how startups apply, what happens after investment and which mistakes can put investor tax relief at risk.

Key Takeaways

• SEIS is designed to encourage individuals to invest in small, early-stage, higher-risk trading companies.
• A qualifying investor can potentially claim Income Tax relief equal to 50% of the amount invested, subject to the applicable limits and their tax liability.
• The maximum investment on which an individual can claim SEIS Income Tax relief is generally £200,000 per tax year.
• A qualifying company can currently receive up to £250,000 under SEIS, subject to the detailed rules.
• The company generally needs gross assets of no more than £350,000 immediately before the relevant shares are issued.
• The company must have fewer than 25 full-time equivalent employees when the shares are issued.
• The relevant new qualifying trade generally must not have been carried on for more than three years.
• Advance Assurance allows a startup to ask HMRC whether a proposed investment is likely to qualify before the shares are issued.
• Advance Assurance is not mandatory.
• Advance Assurance is not a guarantee that an individual investor will receive tax relief.
• HMRC normally wants evidence of genuine fundraising activity rather than speculative applications.
• Receiving Advance Assurance does not complete the SEIS process: after the investment the company still needs to satisfy the conditions and submit an SEIS compliance statement before investor certificates can be issued.

What Is SEIS?

The Seed Enterprise Investment Scheme (SEIS) is a UK venture capital tax-relief scheme intended to encourage investment in small, early-stage companies.

The basic concept is:

Investor puts capital at risk in an eligible startup → qualifying investment receives significant tax incentives

The tax relief helps compensate investors for accepting the high risk associated with early-stage companies.

For startups, SEIS can therefore become an important fundraising tool.

A founder might be raising:

£200,000 from UK angel investors

Two startups may offer similar commercial opportunities.

But if one investment potentially qualifies for SEIS and the other does not, the after-tax economics for a qualifying investor can be very different.

What Tax Relief Can SEIS Investors Receive?

SEIS potentially provides several forms of investor tax relief.

The main ones include:

1. Income Tax relief
2. Capital Gains Tax disposal relief
3. Capital Gains Tax reinvestment relief
4. Potential loss relief

Each has separate conditions.

1. Income Tax Relief

The headline SEIS benefit is:

50% Income Tax relief

on qualifying investment.

An investor can generally claim relief on qualifying SEIS investments of up to:

£200,000 per tax year

for shares issued on or after 6 April 2023.

This means the maximum headline Income Tax reduction can potentially be:

£100,000

for the tax year.

However, the relief cannot reduce the investor's Income Tax liability below zero.

Example: £50,000 SEIS Investment

Suppose an angel investor subscribes:

£50,000

for qualifying SEIS shares.

Potential Income Tax relief:

£50,000 × 50% = £25,000

If the investor has sufficient UK Income Tax liability and satisfies the other investor conditions, their effective initial economic exposure may therefore look like:

Investment: £50,000

Potential Income Tax relief: £25,000

Net cost after Income Tax relief: £25,000

This does not mean the investment is safe.

The investor has still invested £50,000 in a high-risk startup and may lose the investment.

The tax relief simply changes the investor's after-tax economics.

Carry Back

SEIS also contains a carry-back mechanism.

An investor may elect to treat some or all of qualifying shares issued in one tax year as if they had been issued in the preceding tax year, subject to the applicable conditions and limits.

This can be particularly useful for investors who had a larger Income Tax liability in the previous year.

For example:

Shares issued: 2026/27 tax year

The investor may potentially elect to treat some or all of the qualifying subscription as made in:

2025/26

subject to the applicable rules and available limits.

2. Capital Gains Tax Disposal Relief

SEIS can also provide favourable Capital Gains Tax treatment when qualifying shares are eventually sold.

Broadly, where the investor receives the relevant SEIS Income Tax relief and the qualifying conditions continue to be met, a gain on disposal of the SEIS shares after the required holding period may be exempt from Capital Gains Tax.

The relevant holding period is generally:

at least three years from the date the shares were issued

subject to the detailed conditions.

This creates a powerful combination:

Income Tax relief when investing

plus potentially:

CGT-free qualifying growth when exiting.

3. SEIS Reinvestment Relief

SEIS can also provide Capital Gains Tax reinvestment relief.

Where an investor realises a gain on another asset and reinvests the relevant amount into qualifying SEIS shares, up to 50% of the qualifying reinvested gain may be exempt from CGT, subject to the applicable conditions.

For the 2025/26 tax year, HMRC states that the maximum SEIS reinvestment relief can be:

£100,000

because it is limited to 50% of the £200,000 maximum amount on which SEIS Income Tax relief can be claimed.

This relief has detailed timing rules and should be considered separately from the ordinary 50% Income Tax relief.

4. What If the Startup Fails?

SEIS does not make startup investing risk-free.

Startups can fail and investors can lose their capital.

However, where qualifying shares are disposed of at a loss, tax relief may potentially be available for the allowable loss after taking account of SEIS Income Tax relief already received.

The precise value depends on the investor's circumstances and tax position.

This is another reason SEIS can materially change the downside economics for qualifying individual investors.

Example: Why SEIS Can Matter to an Angel Investor

Suppose an investor subscribes:

£100,000

for qualifying SEIS shares.

Potential Income Tax relief:

£50,000

The startup succeeds.

After satisfying the applicable holding and scheme conditions, the investor eventually sells the shares for:

£500,000

The resulting qualifying gain may potentially benefit from SEIS disposal relief.

Alternatively, suppose the startup fails.

The investor may potentially have access to loss relief on the remaining allowable loss, subject to their individual tax position.

This asymmetric tax treatment is one reason SEIS is highly relevant to UK angel investing.

How Much Can a Startup Raise Under SEIS?

A company can currently receive a maximum of:

£250,000

through SEIS, subject to the detailed rules.

This is a company-level limit, not the same as the investor's £200,000 annual Income Tax relief limit.

For example:

Investor A: £100,000

Investor B: £75,000

Investor C: £75,000

Total SEIS round: £250,000

The investors then consider their own individual tax-relief limits separately.

Certain other relevant state aid can also affect the company limit, so the £250,000 figure should not automatically be treated as available in every case.

Which Companies Can Qualify for SEIS?

SEIS is aimed at genuinely early-stage businesses.

Among the main company conditions, the company and relevant subsidiaries generally must have:

Gross assets

No more than:

£350,000

immediately before the relevant shares are issued.

Employees

Fewer than:

25 full-time equivalent employees

when the shares are issued.

Trading history

Where the company is already carrying on the qualifying trade, that trade generally must not have been carried on for more than:

3 years

at the relevant point.

The company must also satisfy numerous other conditions concerning its structure, activities, independence and use of funds.

What Is a Qualifying Trade?

The company's trade must generally be conducted commercially with a view to making profits.

However, not every trade qualifies.

Certain activities are excluded.

Examples can include substantial activities involving:

• dealing in land;
• dealing in shares, securities and certain financial instruments;
• banking;
• insurance;
• money lending;
• certain leasing;
• property development;
• farming;
• legal services;
• accountancy services;
• and certain other activities.

The rules contain detailed exceptions and definitions.

A company should therefore not assume:

“We are a UK startup, so we qualify for SEIS.”

The actual business model matters.

The Risk-to-Capital Condition

SEIS is intended for genuine risk capital.

The investment must satisfy HMRC's risk-to-capital condition.

Broadly, there are two elements.

The company must intend to grow and develop over the long term

HMRC may look at expected growth in areas such as:

• revenue;
• customers;
• employees;
• and business activities.

Investors' capital must genuinely be at risk

The investment should carry a significant risk that investors could lose capital.

SEIS is not designed to subsidise investments structured primarily for capital preservation.

Arrangements designed to protect investors from ordinary commercial risk can therefore create problems.

What Is SEIS Advance Assurance?

Advance Assurance allows a company to ask HMRC, before the proposed share issue, whether the investment is likely to meet certain SEIS requirements based on the information provided.

If HMRC is satisfied, it sends the company an Advance Assurance statement.

The company can then show that statement to prospective investors.

Conceptually:

Startup prepares funding round

↓

Startup applies to HMRC

↓

HMRC reviews proposed investment

↓

Advance Assurance issued

↓

Startup shows assurance to investors

↓

Investment completes

↓

Shares issued

↓

Company later completes SEIS compliance process

↓

Investors receive SEIS3 certificates

↓

Investors claim their tax relief

Advance Assurance therefore sits near the beginning of the fundraising process.

It is not the final SEIS approval.

Is Advance Assurance Mandatory?

No.

A company is not legally required to obtain Advance Assurance before issuing SEIS shares.

A startup can potentially complete an investment and then go through the SEIS compliance process afterwards.

However, many angel investors prefer to see Advance Assurance before investing.

Why?

Because without it, an investor may be asked to:

invest first and discover later whether HMRC agrees with the company's SEIS position.

Advance Assurance reduces that uncertainty.

It does not eliminate it.

What Advance Assurance Does — and Does Not — Mean

This distinction is critical.

Advance Assurance does mean:

HMRC has reviewed the proposed investment based on the information provided and considers that certain company/investment conditions are likely to be satisfied.

Advance Assurance does not mean:

• HMRC guarantees the investor's tax relief;
• HMRC has approved the investor personally;
• the startup is endorsed by HMRC;
• the investment is safe;
• HMRC has approved the company's valuation;
• the company can ignore future SEIS conditions;
• or investors can skip their own due diligence.

HMRC specifically warns that Advance Assurance should not be treated as an endorsement of the investment or an indication of investment performance.

Investor Eligibility Still Matters

SEIS has conditions applying to investors as well as companies.

For example, an investor generally cannot have a substantial interest in the company.

Broadly, this can arise where the investor, together with associates where relevant, has more than:

30%

of certain ownership, voting or economic rights.

There are also rules concerning employees and associates.

SEIS contains some special treatment for directors, but investor eligibility should be checked separately.

This is important because:

Company has Advance Assurance ≠ every investor automatically qualifies for SEIS relief.

What Shares Qualify?

SEIS is not available simply because an investor transfers money to the company.

Qualifying shares must satisfy detailed conditions.

Broadly, the relevant shares must be ordinary shares that:

• are subscribed for wholly in cash;
• are fully paid when issued;
• do not carry prohibited preferential rights to dividends;
• do not carry prohibited preferential rights to company assets on winding up;
• and do not carry a right to be redeemed.

This is why the company's Articles of Association and proposed share rights need to be considered before the round closes.

Can a SAFE or ASA Qualify for SEIS?

This requires particular care.

SEIS relief ultimately relates to qualifying shares.

Early-stage UK startups sometimes use an Advance Subscription Agreement (ASA) where investors provide money before the qualifying shares are issued.

HMRC recognises ASAs in the venture capital scheme context, but specific requirements apply.

An ASA intended to support SEIS/EIS treatment should not effectively operate as a loan.

For example, HMRC expects relevant ASAs not to provide:

• repayment rights;
• interest;
• or other loan-like investor protections.

A longstop date is also expected.

This should therefore be structured before money is accepted rather than reconstructed afterwards.

When Should a Startup Apply for Advance Assurance?

A startup should normally consider Advance Assurance when the fundraising proposal is sufficiently developed to give HMRC meaningful information.

That generally means the company knows:

• approximately how much it wants to raise;
• what shares it proposes to issue;
• what the money will be used for;
• what the business does;
• how the company plans to grow;
• and who is genuinely considering investing.

The application should reflect an actual fundraising proposal.

Not merely:

“We might raise SEIS money one day.”

HMRC Does Not Want Speculative Applications

This is an important practical requirement.

For companies that have not previously raised money under SEIS, EIS, VCT or the former SITR scheme, HMRC expects evidence that the company is genuinely seeking investment.

Where the company is raising directly from investors, this generally means providing information about prospective investors.

HMRC's guidance says this will generally include:

• prospective investor name;
• address;
• and intended investment amount.

Alternatively, where fundraising is through a fund manager, business promoter or crowdfunding platform, evidence of their involvement may be used.

So founders should not think:

“First we get Advance Assurance, then we start speaking to investors.”

In practice, some genuine investor engagement may need to happen first.

What Do You Need for an Advance Assurance Application?

HMRC asks for substantial information about the company and proposed fundraising.

The application generally includes:

Proposed raise

How much money the company intends to raise.

Business plan

The business plan should explain:

• the company's activities;
• business model;
• market;
• growth strategy;
• use of investment;
• and likely future funding requirements.

HMRC specifically says this should be a genuine commercial business plan — not a special document created only for Advance Assurance.

Financial forecasts

The company should provide forecasts supporting the fundraising plan.

Accounts

Latest company accounts, if available.

Use of funds

HMRC wants to understand:

What will the investment actually pay for?

For example:

• employees;
• product development;
• software;
• marketing;
• expansion;
• R&D;
• or other qualifying business expenditure.

Articles of Association

An up-to-date copy and details of proposed changes.

Register of members

An up-to-date copy.

Fundraising materials

The latest draft of documents used to explain the investment proposal to potential investors.

Shareholder agreements

Relevant agreements between the company and shareholders.

Prospective investor information

Where required.

Risk-to-capital explanation

The application needs to demonstrate why the company and investment meet the risk-to-capital condition.

The Business Plan Matters

Founders sometimes treat the business plan as an administrative attachment.

HMRC does not.

HMRC's Venture Capital Schemes Manual specifically says that the business plan should be the same type of document that would be shown to genuine potential investors.

It should explain:

• how the investment will be spent;
• what business activity it supports;
• future funding requirements;
• and how the investment will contribute to growth and development.

Depending on the company, this may include forecast growth in:

• revenue;
• customers;
• employees;
• geographic markets;
• or products.

The Advance Assurance application should therefore tell a coherent commercial story.

You Need a UTR Before Applying

A newly incorporated startup should not assume it can apply immediately after Companies House incorporation.

HMRC requires the company to be registered with HMRC and to have obtained its:

Unique Taxpayer Reference — UTR

before submitting an Advance Assurance application.

The application also requires the company's:

Company Registration Number — CRN

This should be factored into fundraising timing.

Example: £250,000 SEIS Round

Imagine a UK SaaS startup.

The company:

• has recently started trading;
• has 5 employees;
• has gross assets of £100,000;
• is developing a subscription software platform;
• and wants to raise £250,000 from angel investors.

The founders intend to use the money for:

£110,000 — engineering hires

£60,000 — product and infrastructure

£50,000 — sales and marketing

£30,000 — other operating costs

The company begins discussions with several angel investors.

Two investors say:

“We are interested, but we want to see SEIS Advance Assurance before completing the investment.”

The startup prepares:

• business plan;
• forecasts;
• proposed investment terms;
• Articles;
• register of members;
• use-of-funds analysis;
• investor information;
• and explanation of its growth strategy.

The company submits an Advance Assurance application.

HMRC reviews the proposed investment and issues Advance Assurance.

The startup can now show that statement to investors.

But the process is not finished.

What Happens After Advance Assurance?

Suppose the angels proceed.

Step 1 — Investment documents are completed

The company executes the relevant subscription and corporate documents.

Step 2 — Investors transfer the money

Cash reaches the company's bank account.

Step 3 — Qualifying shares are issued

The share issue must comply with the relevant SEIS requirements.

Step 4 — Company records are updated

This can include:

• register of members;
• cap table;
• accounting records;
• and Companies House filings such as SH01 where required.

Step 5 — Company continues satisfying SEIS conditions

Advance Assurance does not freeze the facts.

Material changes can affect the position.

Step 6 — Company submits its SEIS compliance statement

This is the SEIS1 stage.

Step 7 — HMRC authorises investor certificates

If HMRC accepts the compliance statement, the company can issue the relevant SEIS certificates.

Step 8 — Investors claim tax relief

Investors use their SEIS3 certificates to support their individual tax claims.

When Can the Company Submit SEIS1?

The company cannot necessarily submit its SEIS compliance statement immediately after the investment.

HMRC states that the company generally cannot submit SEIS1 until at least one of the following is true:

Trading condition

The qualifying trade has been carried on for at least:

4 months

or

Spending condition

At least:

70% of the money raised by the relevant share issue

has been spent for the qualifying business activity for which it was raised.

This creates an important distinction:

Advance Assurance before investment

versus

SEIS compliance certification after investment and the relevant conditions are met.

Advance Assurance vs SEIS1 vs SEIS3

These three concepts are often confused.

A founder should not tell an investor:

“We have Advance Assurance, so you can claim the relief now.”

Advance Assurance alone is not the investor's tax certificate.

What Happens If the Company Changes the Deal?

This is another important point.

Advance Assurance is based on the information supplied to HMRC.

If material facts change between the application and the actual investment, the original assurance may no longer be reliable.

Examples might include changes to:

• share rights;
• investment structure;
• use of funds;
• company activities;
• Articles;
• investor arrangements;
• or other material facts.

HMRC specifically requires companies to disclose changes when later submitting the compliance statement.

The rule founders should follow is simple:

Do not obtain Advance Assurance for one transaction and then close a materially different transaction without reviewing the SEIS implications.

Common Founder Mistakes

SEIS and Your Accounting Records

SEIS investment is financing.

It is not customer revenue.

Suppose investors subscribe:

£200,000

for newly issued ordinary shares.

The company's bank balance increases by:

£200,000

but revenue does not increase by £200,000.

The transaction is recorded as an equity financing transaction according to the applicable accounting treatment.

The company's records should reconcile:

Investment agreements

↓

Bank receipts

↓

Share allotments

↓

SH01

↓

Register of members

↓

Cap table

↓

Accounting records

↓

SEIS documentation

This becomes particularly important during the company's next funding round.

SEIS and Fundraising Due Diligence

Future investors may ask for:

• Advance Assurance;
• SEIS1 documentation;
• SEIS3 records;
• share subscription agreements;
• Articles of Association;
• shareholder agreements;
• board resolutions;
• shareholder resolutions;
• SH01 filings;
• register of members;
• cap table;
• bank statements;
• and accounting records.

The objective is reconciliation.

For example:

SEIS investment received: £250,000

Bank receipts: £250,000

Subscription agreements: £250,000

Shares issued: agree to subscription documents

SH01: agrees to shares issued

Register of members: agrees to shareholders

Cap table: agrees to statutory ownership

Accounting records: agree to financing

SEIS documentation: agrees to qualifying share issue

Clean records at the first angel round make later due diligence much easier.

Practical Recommendations for UK Founders

Check SEIS eligibility before marketing the round as SEIS

Do not promise tax relief before checking the company's circumstances.

Start investor conversations early

First-time Advance Assurance applications generally need evidence of genuine fundraising interest.

Obtain the company's UTR

You need it before applying for Advance Assurance.

Prepare a real business plan

Use the same commercial plan you would show investors.

Explain use of funds clearly

Connect the investment to actual growth and development.

Review the share rights

Do this before issuing shares.

Review investor eligibility separately

Advance Assurance does not confirm each investor's personal entitlement.

Avoid guaranteed returns and downside protection

SEIS is intended for genuine risk capital.

Keep the round consistent with the Advance Assurance application

If the structure changes materially, review the tax implications.

Record investment as financing, not revenue

Keep accounting and legal records aligned.

Track the SEIS1 milestone

Know when the four-month trading or 70%-spending condition allows the compliance statement to be submitted.

Give investors their SEIS3 certificates promptly once authorised

Tax certificates are part of the investor experience.

How Agbis Helps

SEIS Finance & Readiness Review

We help UK startups organise the financial information and records needed around early-stage fundraising.

We can review:

SEIS financial readiness

Advance Assurance financial information

Business plan financial forecasts

Use-of-funds schedules

Investor payment reconciliations

Share capital accounting

Cap table reconciliations

SEIS1 financial records

Companies House accounting records

Investor-ready bookkeeping

Fundraising due diligence

SEIS involves detailed tax and legal requirements. Eligibility, share rights and investment documents should also be reviewed by appropriately qualified UK tax and legal advisers.

Disclaimer: This article is for general information only and is not legal, tax or investment advice. SEIS eligibility depends on the facts of each company and investor. Consult qualified UK tax and legal advisers.