What is a SeedFAST and how does it compare to a standard ASA?

Key facts

• A SeedFAST is SeedLegals' branded template for an advance subscription agreement — legally, it is an ASA.
• The same HMRC conditions decide SEIS/EIS compatibility: non-refundable, interest-free, no variation, ordinary shares only, longstop within six months.
• SEIS relief is worth 50% of the amount invested and EIS 30% — whichever template you use, breaching the conditions loses it.
• Relief arises when shares are issued at conversion, not when the SeedFAST or ASA is signed.

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What exactly is a SeedFAST?

A SeedFAST is the name SeedLegals — a UK legal-documents platform — gives to advance subscription agreements generated on its service. The name is a brand, not a separate legal instrument: a SeedFAST is an ASA.

An ASA, briefly, is an advance payment for shares. The investor pays now — irrevocably, non-refundably and without interest — and receives shares at your next qualifying funding round, or on a longstop date if no round arrives first.

This page sticks to the comparison; the full mechanics, conditions and negotiation points of ASAs are covered in our main ASA guide, linked under Keep reading below.

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Is a SeedFAST legally different from a standard ASA?

No. The legal substance — an irrevocable, non-refundable advance payment converting into full-risk ordinary shares at the next qualifying round or a longstop date — is the same whether the document came from a platform, a law firm or a well-drafted precedent.

What differs is production. A SeedFAST is generated from a standardised template with configurable terms; "a standard ASA" in practice means any ASA drafted or adapted outside that platform. A court, or HMRC, reads the terms of the document — not the letterhead.

Where outcomes differ between two such agreements, the cause is the specific terms chosen — discount, fallback valuation, qualifying-round definition, longstop — never the brand. Compare terms, not names.

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Do the same SEIS and EIS conditions apply?

Yes, identically. HMRC's advance assurance guidance sets the shape any ASA must take: the payment cannot be refundable, must carry no interest, the agreement must not be capable of being varied, cancelled or assigned, it must convert only into full-risk ordinary shares, and the longstop should sit no more than six months from signing.

Meet those conditions and investors can claim SEIS relief at 50% or EIS at 30% of the amount invested, arising when the shares are issued at conversion. Fail them — on any template — and the relief is at risk.

That is the practical takeaway: SEIS/EIS compatibility is a property of the terms and the company's eligibility, never of the brand on the front page.

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When is a template enough — and when do you need bespoke drafting?

A standardised template fits standardised situations: modest sums, angels investing on ordinary terms, one instrument at a time, nothing unusual attached. That is a real and legitimate use case, and platform templates exist precisely to serve it.

Bespoke drafting or a solicitor's review earns its keep when something is non-standard: several instruments on different terms, an investor demanding special rights, edits to the conversion or refund mechanics (the fastest way to break HMRC's conditions), or sums large enough that a mispriced fallback valuation genuinely hurts.

A sensible middle path: generate the document from the template, then have the configured terms reviewed before signature. The review is checking your choices, which is cheaper than drafting from scratch.

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Worked example

Yusuf, founder of a B2B logistics platform, banks two angels on SeedFASTs in April: £50,000 and £30,000, each with a 10% discount and a six-month longstop. In August he closes a qualifying seed round at £1.20 per share.

Both instruments convert at £1.08 — the round price less 10% — so the angels receive about 46,300 and 27,800 shares respectively, against the roughly 66,700 shares that £80,000 buys new investors at full price. The company allots the shares, files its SH01 within one month, and the angels' SEIS claims run from the August issue date. Had Yusuf's solicitor papered identical terms as a bespoke ASA instead, every one of those numbers would be the same.

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Where founders go wrong

• Assuming the brand changes the law

  — SeedFAST or ASA, the same HMRC conditions decide SEIS/EIS. The tax analysis never reads the logo.

• Editing conversion or refund mechanics

  — adding a refund right, an extension option or a variation clause can void relief on any template. If you must customise, get the change checked.

• Stacking instruments on mismatched terms

  — several SeedFASTs or ASAs with different discounts and fallback valuations multiply into a messy conversion at the round.

• Ignoring the longstop while the round drifts

  — six months passes quickly. Diarise the date and plan conversion mechanics before it hits.

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Related questions

Is a SeedFAST SEIS and EIS compatible?

It is designed to be — but compatibility depends on the same HMRC conditions as any ASA: non-refundable payment, no interest, no variation, conversion into full-risk ordinary shares, and a longstop within six months. Configure or amend the terms outside those lines and relief is at risk, whatever the branding.

What's the difference between a SeedFAST and a SAFE?

A SeedFAST is an ASA — a UK instrument shaped around HMRC's SEIS/EIS conditions, with a longstop date. A SAFE is the US Y Combinator instrument: no longstop, and not SEIS/EIS-compatible as standard without restructuring. UK startups raising from UK angels usually need the ASA family. [More: ASA vs SAFE — which should UK startups use?]

Does a SeedFAST have a longstop date?

Yes — as an ASA it needs one, and HMRC's published expectation for SEIS/EIS is no more than six months from signing. If no qualifying round closes in time, the SeedFAST converts at its fallback valuation on that date. [More: Why do ASAs have a six-month longstop date?]

Do I need a lawyer if I use a SeedFAST?

A standard template can carry a standard deal. Advice earns its keep when anything is non-standard: stacked instruments on different terms, investor-requested edits, a fallback valuation you haven't stress-tested, or a cheque big enough that mistakes compound. A review costs less than unwinding a broken conversion. [More: Can I use legal templates instead of a lawyer?]

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Whether your ASA comes from a platform or a law firm, the terms inside it decide your dilution and your investors' tax relief — and small edits can have outsized consequences. A SuLe solicitor can review the configured terms before your angels sign. Book a free term sheet review and make sure the document does what everyone thinks it does.

Keep reading: What is an advance subscription agreement (ASA)? · ASA vs SAFE — which should UK startups use? · Why do ASAs have a six-month longstop date? · ASA vs convertible loan note — what's the difference? · Do ASAs and convertible notes qualify for SEIS/EIS? · Legal template platforms vs a solicitor — what's the real difference?

Primary sources: HMRC — advance assurance for venture capital schemes · HMRC — Seed Enterprise Investment Scheme