Daně a legislativa ČR
Tax Records of Trades: What to Keep and for How Long
Key takeaways
- Keep records for every purchase: date, number of units, price, currency, fees.
- Broker statements are a good start, but your own records are insurance against a broker change or system outage.
- To prove the time test (3 years) you need to document the exact purchase date.
- The general limitation period for additional tax assessment is 3 years from the end of the filing deadline — keep documents at least that long.
- This is not tax advice — verify the limitation periods with an adviser or in current legislation.
Tax records of trades are not just administrative formality — without purchase records you cannot prove the purchase price or holding period, which are two key factors for calculating taxable gain and claiming an exemption.
What to Keep
For every purchase and sale of a security, archive:
- Transaction date (purchase and sale)
- Name and ISIN of the security
- Number of units purchased/sold
- Purchase price per unit and in total (in the transaction currency)
- Transaction fees
- Exchange rate used (if in foreign currency)
- Statement or confirmation from the broker
For dividends, additionally: date credited, gross amount, tax withheld abroad.
Why Broker Statements Alone Are Not Enough
Brokers generally provide statements — but not all keep history indefinitely. If you change broker, the platform shuts down, or it changes systems, historical data may become unavailable. A simple personal spreadsheet (even in Excel or Numbers) is insurance. For the FIFO calculation you need a complete record of every "lot" — see the article on the FIFO method.
How Long to Keep Documents
The general limitation period for additional tax assessment in the Czech Republic is 3 years from the end of the return filing deadline. For a 2026 return (filed by April 2027) that means approximately until 2030. However, for long-term investors who hold securities for years or decades: keep purchase documents for the entire holding period plus several additional years. If you claim the time test, you need to prove the purchase date — and it must match the document. Verify specific periods with a tax adviser.
How to Connect Records to Your Tax Return
When filing your return you will draw on your own records — the amounts of income, purchase prices, and exchange rates used. How to fill in the return correctly is described in how to file a tax return as an ETF investor. Currency conversion is covered in exchange rates and converting gains to Czech crowns.
This article is not tax advice. Deadlines and obligations may change — verify the current legislation or consult a tax adviser. See also ETF taxes in the Czech Republic.
FAQ
Do I need to keep broker statements if I have online access to history?
Online access is not sufficient insurance — brokers may change systems, shut down, or restrict access to historical data. Download statements regularly and save them locally or in the cloud. Physical or PDF documents are reliable.
How long exactly must I keep documents?
The general tax limitation period is 3 years from the end of the return filing deadline. For securities you hold for a long time, keep purchase documents for the entire holding period and then for several more years. Verify specific periods with a tax adviser.
What if I did not keep old statements?
Try to obtain them retrospectively from the broker — many brokers archive transactions for at least 5–10 years. If data are missing, deal with the situation with a tax adviser in advance, not when the tax authority comes calling.