Documentation: Jahressteuerbescheinigung, Erträgnisaufstellung, Foreign-Broker Records, Retention Periods and Software

What you will learn

• What the Jahressteuerbescheinigung and the Erträgnisaufstellung contain and which one the tax office needs.
• How to build a tax file for a foreign broker, including the euro conversion of each trade.
• Which retention periods apply and how the assessment limitation period sets the real minimum.
• What software can and cannot do for you.

Explanation

With a German bank, documentation is largely done for you; with a foreign broker or crypto exchange you are the bookkeeper. The forms are covered in lesson 5; this lesson is about the evidence behind the numbers.

Documents from a German bank

The Jahressteuerbescheinigung (annual tax certificate under §45a EStG) is the official document: it shows, in the exact order of the Anlage KAP lines, your capital income, the Sparer-Pauschbetrag used, the losses in each pot, the foreign withholding tax credited and the German tax withheld. It arrives between February and April and is the only bank document the tax office accepts as proof of withholding. The Erträgnisaufstellung (income statement) lists every dividend, interest payment, Vorabpauschale and sale with its tax calculation; it is your tool for checking the certificate. Keep both, plus any Verlustbescheinigung (lesson 3) and the custody statement as of 31 December.

Foreign brokers: build the file yourself

A foreign broker withholds no German tax and issues no German certificate. Per calendar year you need: the full trade list with dates, quantities, prices, fees and currency; dividends and interest with foreign tax withheld; corporate actions (splits, spin-offs, mergers change acquisition costs); and the year-end position statement. Two rules:

• Convert every transaction separately into euro at the rate of its own day. The gain is euro proceeds minus euro cost, not the dollar gain converted at the sale date; currency moves are part of the taxable result under §20. The ECB reference rate is a widely accepted source; use one source consistently and keep the rate table.
• Apply FIFO yourself per security and broker account, exactly as a German bank would, and keep the lot-by-lot calculation.

For crypto, the BMF letter of 6 March 2025 (lesson 8) sets the standard: a traceable report per sale with the software settings. Download exchange histories every year; data from an insolvent exchange is hard to recover.

Retention periods

Private investors have no general statutory retention duty, with one exception: if positive surplus income (capital, rental and other income) exceeds €500,000 in a year, §147a AO requires six years of records. For everyone else the practical rule comes from the Festsetzungsfrist (assessment limitation period): four years from the end of the year in which you filed, or at the latest from three years after the tax year if you never filed. Within that window the office can change the assessment and you carry the burden of proof; for careless under-declaration the period is five years, for tax evasion ten. Rule of thumb: keep investment records for at least ten years, and purchase documents for as long as you hold the asset plus ten years.

Software

Three categories help: the official ELSTER portal for filing; portfolio trackers that import broker statements and compute FIFO gains in euro; and crypto tax tools that read wallets and exchanges and produce the BMF report format. None removes your responsibility: check imported rates, corporate actions and transfers between your own accounts, and export each year's final report as PDF and CSV.

Worked example

Hypothetical example: US shares at a foreign broker, fees $10 per order; Sparer-Pauschbetrag, church tax and dividends ignored.

• Buy 100 shares at $150 = $15,000 plus $10 fee = $15,010; EUR/USD that day 1.10 → €15,010 / 1.10 = €13,645.45.
• Sell 100 shares at $180 = $18,000 minus $10 fee = $17,990; EUR/USD that day 1.20 → €17,990 / 1.20 = €14,991.67.

Taxable gain: €14,991.67 − €13,645.45 = €1,346.22 (unrounded: €1,346.21). The dollar gain was $2,980, which would be €2,483.33 at the sale-day rate, but that is the wrong method: the dollar weakened between purchase and sale, and the euro result is what German law measures. Tax at 26.375 percent: about €355.06, declared in the Anlage KAP lines for income without German withholding. The file for this trade: both confirmations, the two exchange rates with source, and the FIFO lot sheet.

Common mistake

Practice activity

On paper: buy 50 shares at $200 plus $10 fee when EUR/USD is 1.05; sell 50 shares at $210 minus $10 fee when EUR/USD is 1.25. (a) Calculate the gain in dollars and the taxable gain in euro. (b) The investor files the 2026 return in May 2027; until the end of which year can the tax office normally change the assessment, and until when if no return had been filed?

Key takeaways

• The Jahressteuerbescheinigung is the official proof of withholding; the Erträgnisaufstellung is your checking tool.
• For foreign brokers, convert each trade into euro at its own date, apply FIFO yourself and keep the rate source.
• The assessment period is usually four years from the end of the filing year, longer if you never filed or under-declared; keep records ten years.
• Software helps with imports and FIFO but you remain responsible; export every year's report.

Next step

The last lesson puts everything together in a year-end checklist and a personal tax calendar for investors and traders.