About
A calculator, not an adviser
Vantanomic works out Irish Capital Gains Tax and ETF Exit Tax from your own transaction history, under the FIFO rules Revenue requires. It is a tool for arriving at a number — not a substitute for advice on what to do about it.
What it does
Turns a CSV into a tax position
You export a transaction file from your broker and upload it. The format is detected, columns are mapped, and every disposal is matched against the oldest matching purchase — lot by lot, with fees folded into cost basis on the way in and deducted from proceeds on the way out.
Stocks and ETFs are kept apart because Revenue treats them differently. Stocks are Capital Gains Tax at 33% with the €1,270 annual exemption and loss offset. Irish and EU-domiciled ETFs fall under Exit Tax (41% to 2025, 38% from 2026) with no exemption and no loss offset, while US and OECD-domiciled funds are generally treated as shares. The domicile is read from the ISIN, so the right regime is applied without you having to know which is which.
The output is the set of figures a CG1 or Form 11 asks for, plus the working behind each one. The guides explain the rules themselves in more depth.
What it doesn't do
The boundaries, stated up front
These are easier to read now than to discover later.
It is not tax advice
Vantanomic produces estimates from the data you give it. It is not tax, financial, accounting or legal advice, it takes no account of your individual circumstances, and it is not authorised or regulated by the Central Bank of Ireland. Check your position with Revenue or a qualified professional.
It does not file anything for you
Nothing is submitted to Revenue on your behalf. You file through ROS or on paper; Vantanomic gives you the figures and a pre-filled form to work from.
It does not connect to your broker
There is no account linking and no read access to your holdings. The only way data gets in is a CSV you choose to upload, which also means the figures are only as current as your last import.
Eight-year deemed disposals need your input
Every ETF lot is tracked to its eight-year date and flagged on the dashboard when due. The calculation needs the fund’s market price on that date, which the app has no feed for, so it asks you to supply it.
There is a size limit
Accounts are capped at 2,000 transactions. That covers most retail portfolios comfortably, but it is a real ceiling rather than a soft one.
Some judgements are not ours to make
Where Revenue expects a fund-by-fund assessment — such as whether a particular US-domiciled fund is “equivalent” to an Irish one — Vantanomic applies the common default. It cannot know how a specific fund should be characterised.
Your data
It stays yours
Transactions are stored against your account and protected by row-level security, so no other account can read them. There are no broker credentials to steal, because none are ever collected.
You can export everything you have imported at any time, and resetting your portfolio or deleting your account removes it.
Contact
Questions and corrections
If something looks wrong — a figure, a rule, a broker format that will not parse — it is worth telling us. Corrections to the tax content are especially welcome.
See where you stand
Import your transactions and get your CGT and Exit Tax position. No card, no broker credentials.