How long does SEIS advance assurance last?

There is no formal expiry date. The assurance is given on the facts presented and remains meaningful while those facts still describe your raise. It stops being reliable if the amount, share class, trade, investor group or issue date changes materially. Most investors treat an assurance more than nine to twelve months old as stale.

Can an accountant guarantee how quickly HMRC will respond?

No. Advance assurance is a discretionary, non-statutory service with no statutory response deadline and no right of appeal. An adviser controls preparation and submission only. AccTek submits within two working days of receiving complete information; the decision timetable belongs to HMRC.

What slows an advance assurance application down?

Applying without named prospective investors, applying before the company UTR has arrived, a trade description written for investors rather than for HMRC, an unaddressed borderline activity, slow or partial replies to HMRC questions, and applying close to the end of the tax year when volumes rise.

Startups

How Long Does SEIS Advance Assurance Take? (2026/27)

9 August 2026 · 4 min read

HMRC typically responds to an SEIS or EIS advance assurance application in around four to six weeks. The timetable belongs entirely to HMRC — no adviser controls it. Add one to four weeks if HMRC comes back with questions, which it frequently does, and allow three days to two weeks of preparation before submitting. Apply at least eight weeks before your target close.

Written by Godwin Pinto ACA (ICAI), member of ICPA, founder of AccTek and formerly of PwC.

The full timeline, stage by stage

The wait founders actually experience is longer than the HMRC review, because most of the elapsed time sits either side of it.

Stage	Typical duration	Who controls it
Incorporation to UTR arriving	1–2 weeks	HMRC
Getting named investors to a credible schedule	Highly variable	You
Assembling the document pack	3 days – 2 weeks	You
Preparing and submitting the application	2 working days with AccTek	Your adviser
HMRC review	4–6 weeks	HMRC
Follow-up questions, if any	1–4 weeks	Both
Realistic total from a standing start	7–12 weeks

The eight-week rule of thumb assumes your company is already incorporated with a UTR and your investors are lined up. If you are starting from incorporation, plan for closer to twelve.

Why no adviser can guarantee a turnaround

Advance assurance is a discretionary, non-statutory service. HMRC is not obliged to provide it, there is no statutory deadline for a response, and there is no right of appeal against the outcome. Any firm advertising a guaranteed clearance in a fixed number of days is promising something that is not theirs to give.

What an adviser genuinely controls is the preparation and submission. AccTek turns a complete information pack into a submitted application in two working days. Everything after that is HMRC’s timetable.

How long does advance assurance last?

There is no formal expiry date. An advance assurance is given on the facts you presented, and it remains meaningful for as long as those facts still describe your raise.

It stops being reliable when the round changes materially:

A different amount being raised
A different share class, or different rights attaching to the shares
A change in the trade or business model
A materially different investor group
A significantly later issue date, particularly one that pushes the company past an age or size limit
Any fact that was not disclosed in the original application

In practice most investors treat an assurance more than nine to twelve months old as stale and will ask whether anything has changed. If the answer is yes, go back to HMRC rather than rely on it. Non-disclosure invalidates the assurance entirely, which is worse than a refusal because you may not discover it until investors are trying to claim.

Does EIS take longer than SEIS?

No — the review timetable is the same, and a single application can cover both schemes. What differs is the preparation. EIS applications more often generate follow-up questions because there is more to test: the seven-year rule running from first commercial sale, the group employee and gross-asset position, and knowledge-intensive status where claimed. If your EIS position is borderline on age or size, budget for the follow-up round rather than hoping to avoid it.

What makes it take longer

Applying without named investors. Rejected as speculative rather than delayed — you start again.
Applying before the UTR arrives. Returned without assessment.
A trade description written for investors. Generates questions HMRC would not otherwise have asked.
An unaddressed borderline activity. Turns a two-week query into a two-month one.
Slow or partial replies to HMRC. A partial answer usually produces a second round of questions.
End of tax year. Volumes rise sharply as investors rush to use their annual limits before 5 April, and response times stretch with them.

What you can actually do about it

Three things move the total materially, and all three are on your side of the line:

Incorporate early. The UTR is a fixed one-to-two-week wait you can take off the critical path entirely by doing it before you need it.
Fix the investor schedule before applying, not during. This is the single most common cause of a failed first application.
Keep the author of the application available. Whoever wrote it can answer HMRC’s follow-up in a day; anyone else takes a week and often triggers a second round.