CapTrader German Tax Return: Anlage KAP, Tax Reports and Withholding Tax

CapTrader issues no German tax certificate and pays no flat-rate tax on your behalf — you declare your capital income yourself in Anlage KAP (funds in Anlage KAP-INV). The basis is the annual statement from CapTrader's account management, which you export as CSV and upload to capi.tax under Interactive Brokers. This page also answers the usual CapTrader questions about the tax report, tax certificates and withholding tax.

CapTrader and Interactive Brokers

CapTrader is an introducing broker for Interactive Brokers. Your contract and customer service are with CapTrader, but the account is held at Interactive Brokers — according to CapTrader, at Interactive Brokers in Ireland. Statements, confirmations and tax documents therefore come from the IBKR system.

For capi.tax that's good news: your statement is in IBKR format. You choose Interactive Brokers when uploading and don't need to change anything else.

Exporting the annual statement

CapTrader's account management is the Interactive Brokers Client Portal. The menus follow the IBKR portal; labels may vary slightly by language.

1. Log in to CapTrader account management.
2. Open Performance & Reports (German: Performance & Berichte) and go to Statements.
3. Choose the Activity statement. This is the annual statement CapTrader recommends as the basis for your taxes.
4. Period: Annual and the tax year.
5. Format: CSV. PDF is fine for your records, but capi.tax can only read the CSV.
6. Generate the statement and save the file.

German or English as statement language doesn't matter. If you already use a Flex Query, you can upload its XML instead — the settings are in the Interactive Brokers guide.

Is there a CapTrader tax report?

Under Performance & Reports → Tax Documents you'll find several documents, but none of them is a tax certificate:

• Dividend report: a list of your dividends with the withholding tax deducted. Handy for cross-checking the dividend rows.
• Dividend voucher (Dividendenbeleg): a paid withholding tax certificate for a single dividend. You mainly need it if you want to reclaim excess withholding tax abroad (see below).
• US tax forms such as the 1042-S concern US withholding, not German tax.

Your tax return is based on the annual statement. What it lacks is the calculation under German rules: FIFO, converting each trade at the Bundesbank rate and splitting the results across the lines of Anlage KAP. That is exactly what capi.tax does with the CSV file.

Withholding tax at CapTrader

Withholding tax is deducted not by CapTrader but by the country where the company is based. It appears in your statement in the Withholding Tax (Quellensteuer) section. In Germany you can credit it against your flat-rate tax — but only up to the rate allowed by the double tax treaty (DTT), and at most 25 % of the income (§ 32d (5) EStG).

The US and the W-8BEN. When you open the account, you fill in Form W-8BEN. With it, the US withholds only 15 % on dividends, and those 15 % are fully creditable. If the form is missing or has expired, 30 % is withheld, but still only 15 % is credited. CapTrader asks you to confirm your details periodically — do it, or you'll pay extra.

Example: Switzerland (example values). A Swiss share pays you a dividend worth €400.00 gross. Switzerland withholds 35 %, i.e. €140.00. Under the treaty, only 15 % is creditable in Germany:

• creditable: 15 % × €400.00 = €60.00 → line 41 of Anlage KAP
• not creditable: 140.00 − 60.00 = €80.00

The credit also never exceeds the German tax on that income: if the saver's allowance covers it, the credit lapses — it cannot be carried forward.

You don't get the €80.00 back through your German tax return, only through a refund claim with the Swiss tax administration. That usually requires proof of the dividend — which is what the dividend voucher is for. capi.tax computes the credit per dividend and per country and shows the creditable amount, not the amount withheld. More in Withholding tax.

Uploading to capi.tax and copying the lines

1. On capi.tax, choose Interactive Brokers and the tax year.
2. Upload the CSV file. It never leaves your browser.
3. Read the processing notices and resolve open points, such as the fund type of your ETFs.
4. Take the values from the KAP Form tab.

The tax: exactly as with Interactive Brokers

Because no German tax was withheld, you have to report the income yourself (§ 32d (3) EStG). Share gains and losses, options, dividends and interest go in Anlage KAP; ETFs and funds go gross in Anlage KAP-INV. The table with all lines and a worked example is in the Interactive Brokers guide.

Example: an assigned short put

Many CapTrader clients trade options. Say you sell a put on a US stock with a strike of USD 50 and receive a USD 200.00 premium. At expiry it is assigned: you buy 100 shares at USD 50 each. With an example rate of 1.0850 USD/EUR on both days:

• option-writer premium: USD 200.00 = €184.33, income in its own right under § 20 (1) no. 11 EStG
• cost of the shares: USD 5,000.00 = €4,608.29 — it only counts when you sell the shares

So the premium is not netted against the share purchase. More in Options & option writing.

What capi.tax does not cover

• Corporate actions (splits, spin-offs, mergers): reported, not applied — see Corporate actions.
• Currency gains on foreign-currency cash: not computed. Depending on whether the balance earns interest, they belong on Anlage SO or (on the disputed view of the tax authorities) on Anlage KAP — see Currency gains.
• Purchases from earlier years: one file per run. Add missing purchases as opening positions — see Your input.

Frequently asked questions

Do I get a tax certificate from CapTrader?

No. Because the account is held abroad at Interactive Brokers, CapTrader issues no tax certificate under German law. Your annual statement is the evidence for your figures.

Does CapTrader pay capital gains tax for me?

No. CapTrader neither calculates nor pays flat-rate tax. The exception is dividends from German shares: according to CapTrader, German capital gains tax is already withheld there, via the central securities depository Clearstream (§ 44 (1) sentence 4 no. 3 EStG). That generally settles the tax (§ 43 (5) sentence 1 EStG); the dividends belong neither in line 19, nor the tax in line 41. Church tax payers still have to declare them for church tax (§ 51a (2d) EStG). Crediting the German tax, for example to use the saver's allowance or offset losses (§ 32d (4) EStG), normally requires a tax certificate under § 45a (2) EStG, which IBKR does not issue — this is not conclusively settled, so clarify your case with a tax advisor. ⚠️ capi.tax does not handle this case separately and may currently book these dividends into line 19 and the tax into line 41; check dividends and withholding tax by country in the overview.

Where do I find the withholding tax at CapTrader?

In the annual statement, in the Withholding Tax section right next to the dividends, and in the dividend report under Tax Documents. capi.tax reads it from the statement and matches it to the respective dividend.

Can I deduct margin interest or CapTrader fees?

No. Beyond the saver's allowance, no actual costs are deductible (§ 20 (9) EStG). Commissions on buys and sells, however, are part of the cost basis or reduce the proceeds — capi.tax accounts for them there.

Ready? Upload your CapTrader statement and choose Interactive Brokers.

capi.tax prepares your data and is not tax advice. Please check the numbers and consult a tax advisor for your personal situation.

Last updated: October 10, 2026