SEIS Explained: 50% Tax Relief on Seed-Stage Investing

The Seed Enterprise Investment Scheme (SEIS) offers the single highest personal income tax relief available in the UK: 50% on investments up to £200,000 per tax year. Launched in 2012 to complement the Enterprise Investment Scheme (EIS), SEIS targets an even earlier stage of company development — businesses at inception or in their very first years of trading.

For additional rate taxpayers and sophisticated angel investors, the SEIS tax advantage is remarkable. An investment of £200,000 can generate £100,000 of income tax relief in a single year. The flip side is that seed-stage investing is among the highest-risk activity available to individual investors: many of these companies will fail.

This guide explains how SEIS works, how it differs from EIS, and the profile of investor for whom it is most relevant.

What SEIS Is

SEIS is a government tax incentive scheme administered by HMRC. It provides income tax relief, capital gains tax relief, and loss relief to individual investors who subscribe for qualifying shares in very early-stage UK companies.

The scheme was introduced to address a well-documented funding gap at the pre-seed and seed stages: the point where a business has a concept and perhaps a founding team but insufficient track record to raise from venture capital funds or even most business angels.

SEIS was made permanent in the Autumn Statement 2022, with the annual investor limit increased from £100,000 to £200,000, and the company gross assets limit increased to £350,000.

The Reliefs in Detail

Income Tax Relief: 50%

Investors receive an income tax reduction equal to 50% of the amount invested. This applies to investments up to £200,000 per individual per tax year.

• Investment of £200,000 → income tax reduction of £100,000
• Investment of £100,000 → income tax reduction of £50,000

The relief is a direct reduction in the investor's income tax bill, not a deduction from taxable income. You must have sufficient income tax liability to absorb the relief in the relevant year. Any excess cannot be carried forward (though you can carry back to the prior tax year).

Shares must be held for at least three years. If disposed of earlier, the income tax relief is clawed back.

CGT Reinvestment Relief

Any capital gains realised on the disposal of any chargeable asset (not just investments) can be exempt from CGT if the proceeds are reinvested into SEIS shares in the same tax year or the following year.

This is different from EIS deferral relief. Under SEIS, gains reinvested into SEIS shares are exempt from CGT (up to 50% of the investment amount matches the gain reinvested). This is a permanent exemption, not a deferral.

Example: a £60,000 capital gain arising from an asset sale. Reinvest £120,000 into SEIS shares. Because SEIS reinvestment relief exempts 50% of the amount reinvested (50% × £120,000 = £60,000), the whole £60,000 gain can be exempt permanently (not deferred). Additionally, the £120,000 investment attracts 50% income tax relief (£60,000).

Combined, the CGT saved plus income tax relief of £60,000 substantially offsets the cost of the £120,000 investment.

CGT Exemption on Gains

If SEIS shares are held for three years and then disposed of at a profit, the gains are entirely exempt from capital gains tax (provided income tax relief was claimed on the shares and has not been withdrawn).

Loss Relief

If an SEIS investment fails, the net loss after income tax relief can be set against income tax at the investor's marginal rate.

Example:

• Investment: £50,000
• Income tax relief received: £25,000
• Net cost to investor: £25,000
• Company fails: £25,000 loss
• Loss relief at 45%: £11,250
• Total money returned through tax reliefs: £36,250
• Effective maximum loss: £13,750 on a £50,000 commitment

The loss relief provision means the financial downside of a seed investment — even if it fails completely — is substantially cushioned by the UK tax system.

SEIS Qualifying Conditions

For a company to qualify for SEIS:

• It must be incorporated in the UK and carry on a qualifying trade
• Gross assets must not exceed £350,000 at the time of investment
• The company must have fewer than 25 full-time employees
• The company must have been trading for fewer than three years
• The company must not have previously carried out a different trade (anti-avoidance rule)
• Excluded activities include: property investment, financial services, energy generation (some categories), legal services, and accountancy

A company can raise a maximum of £250,000 under SEIS (lifetime). After exhausting SEIS eligibility, it may progress to raise under EIS.

Advance assurance from HMRC is strongly advisable before investing. The SEIS3 certificate confirming eligibility is issued after investment and is required to claim relief.

SEIS vs EIS: Understanding the Stage Difference

	SEIS	EIS
Income tax relief	50%	30%
Annual investor limit	£200,000	£1,000,000 (£2m KIC)
Company age	Under 3 years trading	Generally up to 7 years
Company size (employees)	Under 25	Under 250 (500 for KIC)
Company gross assets	Under £350,000	Under £30 million (from Apr 2026; was £15m)
Maximum company raise	£250,000 lifetime	£10m/year (£20m/year KIC); £24m lifetime (£40m KIC)
CGT on gains	Exempt (after 3 years)	Exempt (after 3 years)
IHT (BPR)	After 2 years	After 2 years
Stage	Pre-seed / seed	Early to growth stage

SEIS and EIS are sequential: a company may raise under SEIS first, then progress to EIS fundraising. An investor can also invest in both the SEIS and EIS tranches of the same company (at different times), claiming the respective reliefs separately.

The "Supercharged Angels" Profile

SEIS is particularly used by a specific category of investor: experienced, wealthy individual angels who:

1. Have surplus income tax liability (typically £50,000+ per year) they wish to shelter
2. Have personal connections to founders or sectors (technology, healthcare, consumer, deep tech)
3. Understand that seed-stage investing means accepting total loss as a real possibility
4. Are building a portfolio approach — typically 10–20 SEIS investments spread across vintages
5. Are motivated partly by personal engagement (advising, mentoring, network introductions) not just financial return

These investors treat the SEIS tax relief as a floor: even if every investment fails, the maximum loss on a £200,000 SEIS portfolio (after income tax relief and loss relief) is approximately £35,000–40,000 for a 45% taxpayer. A single successful exit returning 10× can make the entire portfolio profitable, even with many failures.

This loss-protected, high-upside structure is sometimes called the "SEIS lottery ticket" — relatively small effective downside with asymmetric upside.

SEIS Funds

For investors who want SEIS exposure without making individual company selections, SEIS funds are available. These are managed by FCA-regulated investment managers and typically:

• Invest across 15–30 companies per cohort
• Make initial investments of £5,000–£15,000 per company
• Reinvest if portfolio companies progress
• Charge management fees (typically 1.5–2.5%) and carry (20–25%)

SEIS funds are appropriate for investors seeking diversification at the seed stage without the time commitment of direct angel investing. The major risk is that diversification across 30 seed-stage companies still cannot eliminate the possibility of very poor overall portfolio returns.

Accessing SEIS Opportunities

SEIS deals can be sourced via:

• Crowdfunding platforms: Seedrs and Crowdcube list SEIS-eligible deals (typically smaller tickets of £500–£5,000 per company)
• Angel networks: UKBAA members; local angel groups (London Business Angels, Cambridge Angels, etc.)
• SEIS-specific funds: a number of FCA-regulated managers run SEIS-focused funds
• Wealth Club: curates higher-quality SEIS and EIS opportunities for wealthier investors
• Accountants and IFAs: advisers with FCA permissions may introduce clients to SEIS opportunities

Key Risks

SEIS investing is inherently high-risk:

• Most seed-stage companies fail: attrition rates at the seed stage are high; a failure rate of 60–70% across a portfolio is not unusual
• Illiquidity: there is no secondary market for SEIS shares; expect a five to ten year horizon (or longer) before any liquidity event
• HMRC compliance: if the company breaches SEIS conditions, reliefs may be withdrawn with interest
• Dilution: subsequent funding rounds dilute early SEIS investors; the investor's percentage ownership can fall dramatically
• Fund manager quality: for SEIS funds, manager selection is critical and performance data is thin

SEIS is appropriate for sophisticated investors who have maximised pension and ISA contributions, have a clear tax liability to shelter, can afford to lose their entire investment, and have a genuine tolerance for the risks of early-stage business.

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The value of SEIS investments can fall to zero. Tax reliefs depend on individual circumstances and current legislation, which may change. This article is for information only and does not constitute financial or tax advice. Seek qualified advice before investing.

How Global Investments can help

Global Investments advises HNW clients on incorporating SEIS into their annual tax planning strategy — particularly those with high income tax bills or capital gains looking for legitimate tax-efficient deployment. We work with FCA-regulated SEIS fund managers and can help clients assess whether SEIS is appropriate for their risk profile, tax position, and investment horizon. Contact our team to discuss how seed-stage investing might fit within your broader portfolio.