Seisly Reviews 

2
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TrustScore 4 out of 5

3.8

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Company details

  1. Tax consultant
  2. also in
  3. Business-to-Business service
  4. Investment service
  5. Legal Services

Written by the company

Need SEIS or EIS advance assurance? Seisly done. Seisly is a co-pilot for UK startup founders raising under SEIS and EIS. We prepare your full HMRC advance assurance application, draft the covering letter, and can file it for you as your appointed agent, with expert review from a Chartered Tax Adviser. We also advise on equity structuring and EMI option schemes. Around that sits a workspace for the rest of the raise: one profile for your company, an investor directory to find and research who to approach, and fundraising documents. Built by the founder of the UK's first SEIS fund, working with startups on SEIS and EIS since 2012.


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3.8

Great

TrustScore 4 out of 5

2 reviews

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Rated 5 out of 5 stars

Founder raising under SEIS/EIS

As a founder raising under SEIS/EIS, I needed HMRC advance assurance. Sanjay at Seisly handled the whole thing. He reviewed our business plan, projections and investor deck, drafted all the HMRC narrative, and submitted on our behalf. We had advance assurance back within a week, exceeding my expectations. Sanjay flagged the things that actually mattered, told me exactly what to tidy up, and turned a fiddly piece of tax admin into something genuinely straightforward. If you are a startup founder trying to get SEIS/EIS assurance without the usual back and forth, I would recommend Seisly without hesitation.

30 September 2026
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Reply from Seisly

Thank you, Vivek. Glad we could get Scalux AI's advance assurance turned around quickly and that the process felt clear throughout. Best of luck with the round.

Rated 5 out of 5 stars

Would recommend to anyone for fast support

We worked closely with Seisly and would recommend them to anyone for support that is personalised and exceptionally fast. As a startup founder I needed someone to help me understand things and get it actioned, and I got exactly what I needed!

30 September 2026
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Reply from Seisly

Thank you, Sarah. Personalised and fast is exactly what we aim for, so it means a lot to hear it landed that way. Delighted to have helped on the raise, and wishing you and Now Found every success.

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