SEIS Advance Assurance: The Founder’s Guide

SEIS advance assurance is HMRC looking at your plans before you raise and saying, informally, this looks like it should qualify for SEIS. It is not compulsory and it is not a guarantee, but seasoned investors treat it as table stakes, and applying properly is the single best way to find problems while they are still cheap to fix. Here is how it works, what to prepare, and how long it takes.

What SEIS advance assurance actually is

A letter from HMRC’s Venture Capital Reliefs team stating that, based on what you have shown them, they would expect your proposed share issue to qualify. It binds nobody: if reality departs from the application, the letter means nothing. What it really does is de-risk the conversation, for investors, who will not chase relief HMRC has doubts about, and for you, because a refusal now is a problem found early. Investors still do their own checks, and this is a signal, not a guarantee.

Do you need it?

Legally, no. Practically, yes if you are raising from strangers. Friends-and-family rounds occasionally skip it; angel networks and syndicates almost never will. The exception worth knowing: HMRC will not consider speculative applications, so you need to be able to name likely investors or the platforms you will raise through.

The document pack

The application form is online, and the pack behind it is where founders win or lose time. Prepare:

• The business plan and financial forecasts you are actually showing investors, not a cleaned-up special.
• The pitch deck, if that is your raise document.
• Accounts, if any exist yet.
• Incorporation details and articles, plus the shareholder register as it stands.
• How much you are raising, on what instrument, and from whom: named investors, or the platform or network.
• What the money will be spent on, mapped to the qualifying trade.

Everything must tell one consistent story. The classic self-inflicted wound is a deck that says one thing and a forecast that says another. Full preparation detail lives in the eligibility guide, because assurance is really an eligibility exam taken early.

How long it takes

Plan for several weeks; complex cases and busy periods run longer. In 2025 to 2026 HMRC received about 4,085 SEIS advance assurance requests and approved roughly three quarters, so the process is routine for them even when it feels existential to you. Two practical implications: apply before you start closing investors, and never promise a completion date that assumes HMRC moves quickly.

If HMRC says no, or asks questions

Questions are common and usually answerable: they want clarification on the trade, the use of funds, or the structure. A refusal is rarer and usually means a real problem, an excluded activity, a risk-to-capital doubt, a structural tangle. That is not the end; it is an early, free consultation telling you what to fix, sometimes with professional help, before any investor money is at stake.

After assurance: do not drift

The letter reflects the application. Change the share class, the amount, the trade, or the structure between assurance and issue and you may have assured a company that no longer exists. If things change materially, update HMRC or reapply. Then, after the raise itself, remember assurance was step one of the paperwork: the compliance statement and SEIS3 certificates are what actually unlock your investors’ relief.

What HMRC actually checks

Four questions decide most applications, in roughly this order.

• Is the trade qualifying? They read your plan for what the company actually does and test it against the excluded activities list. Vague descriptions invite questions; precise ones close them.
• Where does the money go? Funds must be employed in the qualifying activity. Spending plans dominated by repaying debts, buying assets that look like investments, or anything property-flavoured raise flags.
• Does the structure work? Share classes, the cap table, group relationships and any odd instruments. This is where copied-and-pasted paperwork from other rounds gets caught.
• Is capital genuinely at risk? The risk-to-capital condition filters arrangements engineered for safe, relief-funded returns. Real startups pass by being real startups; contrived structures do not.

The application, field by field

The online form itself is short; the strength is in the attachments. Expect to provide, and to keep consistent with each other:

• Company details, UTR, and the registered and trading addresses
• A description of the trade in commercial English, one that a stranger could restate accurately
• The amount to be raised, the instrument, and the intended share class rights
• How the money will be employed, line by line, against the qualifying activity
• The latest accounts if any, plus forecasts that agree with the deck
• Articles, any shareholder agreements, and the current register
• The names of likely investors, or the platform or network through which you will raise

Reading the letter you get back

An assurance letter is short and conditional. It says that on the facts you presented, HMRC would expect the issue to qualify, and it lists what it relied on. Read it the way your investors will: check the amount, the share class and the described trade match your actual round. If HMRC has caveated anything, that caveat is the to-do list. And keep the letter with the application it answers; the pair travels together into every data room you will ever assemble, alongside the rest of the eligibility evidence.

Assurance and compliance: two different exams

Founders regularly conflate the pre-raise and post-raise paperwork. Advance assurance is the mock exam: optional, informal, sat before the money. The compliance statement, form SEIS1, is the real one: statutory, sat after four months of trading and 70% of the spend, and it is what actually unlocks the SEIS3 certificates your investors claim with. Passing the mock does not sit the real exam for you, and the conditions must be true in fact at issue, not merely plausible in prospect. The claim mechanics your investors will follow are in how to claim SEIS relief.

If the raise changes shape

Rounds move: the amount grows, an instrument changes, a new lead appears. Small drift within the assured description is normal; material change is not covered. A different share class, a materially larger raise, a pivot in the trade, or swapping a named investor base for a crowd platform are all worth an update or a fresh application. The test is simple: if the letter no longer describes your round, stop treating it as if it does.

Planning the raise around assurance

Work backwards from your closing date. Application drafted and filed before you begin serious investor conversations; several weeks of HMRC time while you warm the round; letter in hand as commitments firm up; issue, then the four-month trading clock towards the compliance statement. Founders who file the assurance application the same week they open the round discover that investors move faster than HMRC, and the round stalls at the awkward moment. The checklist plus a tidy data room means the application is a compilation exercise rather than a writing project.

Common questions

How long does SEIS advance assurance take?

Usually a few weeks, varying with HMRC workload and the completeness of your application. Apply before you start closing investors.

How long does advance assurance last?

There is no formal expiry, but it only covers the plans you described. Material changes to the raise, structure or trade mean it may no longer apply.

Is advance assurance a guarantee of SEIS relief?

No. It is HMRC’s informal opinion in advance. Relief depends on the company meeting the conditions at issue and for three years after.

Can I apply without named investors?

Generally no. HMRC does not consider speculative applications, so name likely investors or the platform or network you will raise through.