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Citations first
Every conclusion traces back to the law, a manual or guidance. One click and you are reading the source.
New standard of tax research
GAIN Tax is AI-powered tax and business law research software for accountants, tax advisers and tax lawyers. Every answer is grounded in up-to-date legislation and official guidance with citation to sources, to make verification fast and easy.
Why we built it
Tax research eats hours that should take minutes. General AI models promise to fix that, and they are genuinely fast. The trouble starts when the law moves.
Ask a general model about a rate that changed this April, or a calculation with several moving parts, and it will often give you a wrong answer in a confident voice. In tax work, a confident wrong answer is the most expensive kind.
So we built a tool that shows its working. GAIN Tax retrieves the actual legislation, manuals and guidance, answers from them, and cites them. When its sources do not cover a question, it says so instead of guessing.
We are clear about what GAIN Tax is. It is a research tool that makes tax work faster. It does not replace professional judgment, and we recommend checking every output before it reaches a client.
We also publish our accuracy benchmark in full, including the answers we got wrong. If we expect you to trust the tool, you deserve to see the whole picture.
How it works
Under the hood, GAIN Tax runs retrieval-augmented generation over UK primary and secondary legislation, HMRC manuals and guidance. The library is kept current as the law changes, so answers reflect the right rules for the right tax year.
Client Hub adds the second half: client profiles, documents and history in one workspace, so the AI answers with the full client picture in front of it rather than starting from scratch on every query. Your data is hosted in the UK and never used to train models.
What we stand for
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Honesty over hype
We publish where the tool is strong, where it is weak, and what the risks are.
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Kept current
The library tracks UK tax law as it changes, so you are never advising from last year's rates.
Who we are
GAIN Tax is founded by two brothers. Between them they cover the two things this product has to get right: the tax and the technology.
Co-founder & CEO
Inokentii Kvartirmeister
Finance executive and ACCA-qualified chartered accountant. Inokentii leads the product, the tax standard behind it, and the company.
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Co-founder & CTO
Kostiantyn Kvartyrmeister
AI and technology leader. Kostiantyn builds the retrieval architecture, the infrastructure, and the systems that keep every answer grounded in its sources.
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Run your real UK tax questions through GAIN Tax and check the citations yourself.
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