Taxes · Foreign brokers
Options at a foreign broker: Anlage KAP, deadlines and currency conversion
A broker with no seat or branch in Germany is not a domestic paying agent, so it withholds no German flat-rate tax. Option premiums, option gains and losses, dividends and interest have to be declared by you on Anlage KAP, and that is mandatory (§ 32d(3) EStG). Amounts in US dollars are converted into euros, trade by trade.
By Daniel Berg ·
German flat-rate tax withheld
No
- Return
- Mandatory, Anlage KAP
- Deadline, self-filed
- 31 July of the following year
- Deadline, with an adviser
- End of February, two years on
- Exemption order
- Not possible – allowance given in the assessment
Last reviewed October 2026. General information, not tax advice.
Why a foreign broker withholds no tax
For option premiums and derivatives, the duty to withhold lies with the paying agent, which under § 44(1) sentence 4 no. 1 EStG is a domestic credit, financial services or investment institution (BMF para. 250). A German branch of a foreign institution counts as domestic (§ 43(1) sentence 1 no. 7(b) EStG). A broker serving you from abroad therefore withholds no German flat-rate tax, no solidarity surcharge and no church tax.
That typically covers brokers such as Interactive Brokers that serve German clients through a foreign entity. The simplest test is the paperwork: only German paying agents issue the official German annual tax certificate (Jahressteuerbescheinigung). If you do not get one, you do the maths yourself.
Duty to file and deadlines
Capital income that was not subject to withholding tax must be declared in your income tax return, and an assessment is then carried out (§ 32d(3) sentences 1 and 3 EStG, BMF para. 144). The tax office levies the 25 % flat tax plus solidarity surcharge on it, and church tax where applicable.
| Case | Deadline | For tax year 2026 |
|---|---|---|
| You prepare the return yourself | Seven months after year end (§ 149(2) AO) | 2 August 2027 (31 July is a Saturday) |
| A tax adviser (Steuerberater) prepares it | Last day of February of the second following year (§ 149(3) AO) | 29 February 2028 |
If a deadline falls on a Saturday, Sunday or public holiday, it ends at the close of the next working day (§ 108(3) AO). The tax office can order earlier filing in individual cases (§ 149(4) AO).
What you have to work out yourself
Without a German bank, nobody prepares your trades under German rules; the broker’s statements usually follow its home country’s rules. For Anlage KAP you need, per transaction:
- Option premiums: the premium received at the time of receipt, net of fees. A buyback is negative income at the time of payment (§ 20(1) no. 11 EStG). Details in how option premiums are taxed.
- Long options sold or closed: proceeds minus cost including fees (§ 20(4) sentence 1 EStG).
- Long options expiring worthless: the cost is a loss from a derivative (§ 20(4) sentence 5 EStG, BMF paras. 27 and 32). Since the 2024 Annual Tax Act there is no €20,000 cap – see loss offsetting for derivatives.
- Assignments: on a short put you buy the shares at the strike; on a short call you sell them. Either way the premium stays outside the share transaction (BMF paras. 26 and 33).
- Keep shares separate: gains and losses on shares go in their own lines, because share losses can only be offset against share gains.
Currency conversion: the rate on the day of each transaction
For disposals, § 20(4) sentence 1 EStG is explicit: for transactions not made in euros, proceeds are converted at the time of sale and acquisition costs at the time of purchase. You do not convert the year’s dollar profit at year end; each side of a trade gets its own rate. For running income in foreign currency, German banks use the bid exchange rate on the day the income is received (BMF para. 247).
Made-up rates and amounts for illustration.
- Premium received
- $300
- Rate on sale day
- €1 = $1.10
- Buyback
- $100
- Rate on buyback day
- €1 = $1.05
1Income
$300 ÷ 1.10 = €272.73 premium, taxable as of the sale date.
2Negative income
$100 ÷ 1.05 = €95.24, recognised on the buyback date.
3Result
€272.73 − €95.24 = €177.49 taxable.
Converting the $200 profit at a single rate would give €181.82 or €190.48, depending on which rate you picked. The exchange rate is part of the taxable result.
Getting the figures onto Anlage KAP
Line numbers change with each form year; always use that year’s official instructions. In substance, for the foreign broker you enter:
- 1Foreign capital income not taxed at source – the total after netting: premiums, option gains and losses, dividends, interest, share gains.
- 2Of which gains on share sales – separately, because only they can absorb share losses.
- 3Losses other than share losses – option losses, buybacks, cash settlements (general pot).
- 4Losses on share sales – separately (share pot).
- 5Creditable foreign taxes – for example withholding tax on dividends, capped at 25 % per item of income (§ 32d(5) EStG).
If you also have an account at a German bank, the tax office offsets across all institutions in the assessment (BMF para. 118). Losses at the foreign broker then also reduce gains on which the German bank has already withheld tax – tick the request to review the tax withheld (§ 32d(4) EStG). Losses held at the German bank need its loss certificate, requested by 15 December.
Sources and review date
- § 32d EStG – para. 3 (duty to declare), para. 4 (review), para. 5 (foreign taxes)
- § 44 EStG – paying agent (para. 1 sentence 4 no. 1)
- § 43 EStG – domestic branches (para. 1 sentence 1 no. 7(b))
- § 20 EStG – para. 1 no. 11, para. 4 sentences 1 and 5, paras. 6 and 9
- § 149 AO – filing deadlines
- BMF letter of 14 May 2025 on the flat-rate tax – paras. 26, 27, 32, 33, 118, 131, 144, 247, 250
Frequently asked questions
Do I have to file a German tax return with an Interactive Brokers account?
If you earn taxable capital income there that was not subject to German withholding, yes: § 32d(3) EStG requires you to declare it in your income tax return. Whether that also applies when the income stays below your unused saver’s allowance is worth clarifying if in doubt.
Which exchange rate do I have to use?
The law sets the timing, not the source: proceeds are converted at the time of sale and acquisition costs at the time of purchase (§ 20(4) sentence 1 EStG). German banks use the bid rate on the day income is received. Use one traceable source consistently and keep a record of it.
Can I offset losses at the foreign broker against gains at my German bank?
Yes, in the assessment. The tax office offsets across institutions when you request a review of the tax withheld, and any excess tax the German bank withheld is refunded.
Is US withholding tax on dividends credited?
Foreign tax on capital income is credited against German tax under § 32d(5) EStG, at most 25 % of the item of income and only up to the German tax on that income.
When is the 2026 return due?
If you file yourself, § 149(2) AO sets 31 July 2027; as that is a Saturday, the deadline moves to Monday, 2 August 2027 (§ 108(3) AO). If a tax adviser prepares the return, it is 29 February 2028 (§ 149(3) AO).
Where to go next
All numerical examples in this guide are rounded, illustrative assumptions, not market data. The content is educational and not investment advice. Options are complex instruments; you can lose the entire amount invested, and more than that when selling options.