Webinar: Interactive Brokers Tax Return – Where Trading and Tax Logic Collide
Trading meets German tax logic
In late February, we joined WH SelfInvest and stock3 for their webinar series "Bulle & Bär im Visier" to discuss a topic that affects a surprising number of investors, but is rarely explained systematically:
Why isn't IBKR data enough for a German tax return? And what's concretely missing?
The recording (approx. 51 minutes, in German) is now available on YouTube:
▶ Watch webinar on YouTube (external link, YouTube/Google privacy policies apply)
The core problem
If you trade through Interactive Brokers, whether directly or via an introducing broker like WH SelfInvest, you're in a situation that doesn't exist with German banks: IBKR performs no tax withholding and issues no annual tax certificate. The full tax preparation falls to the investor.
This sounds manageable at first. It isn't, once you look at the details.
Three dimensions that must be correct for every transaction
In the webinar, we showed that every single trade needs to be evaluated from three perspectives:
- Timing: When does something become tax-relevant? Not always when the broker records it.
- Classification: Which tax category applies? A stock is not an ETF is not an option. IBKR data doesn't always make this distinction clear.
- EUR valuation: Every transaction requires the correct ECB exchange rate from the correct day.
Where things break down in practice
We covered cases that come up regularly for IBKR users:
ETF classification: IBKR only knows "ETF." The German tax office distinguishes: Investment fund under InvStG (with partial exemption)? Or ETN/ETC under § 20 EStG? Or gold ETC / crypto ETP under § 23 EStG? This distinction can mean hundreds of euros difference.
Options at year-end: A short put premium in December and the exercise in January are two tax events in two different years. IBKR doesn't present it that way.
Futures and mark-to-market: The broker books daily gains and losses. For tax purposes, however, only the total result upon closing the position counts. The daily entries are tax-irrelevant.
Foreign currency FIFO: The point that surprises most people: USD holdings at IBKR are separate economic assets under German tax law. Buying shares in dollars triggers a dollar outflow that can result in a taxable FX gain, even without a deliberate currency conversion.
Tax buckets: What goes where
Not everything goes into the same loss offset bucket. The short version:
| Bucket | What belongs | Special rule |
|---|---|---|
| InvStG | ETFs & funds | Partial exemption, advance lump sum |
| Stock loss bucket | Stock sales | Losses only offset stock gains |
| Other | Dividends, options, futures, FX | Derivatives cap repealed (JStG 2024) |
Why manual calculation stops working beyond a certain complexity
With 50 trades per year, results can still be verified manually. With multiple currencies, option strategies, and FIFO chains spanning tax years, it quickly becomes error-prone. One forgotten purchase or one wrong exchange rate carries through every subsequent year as an error.
Live demo in the webinar
In the final segment, we showed the BubbleTax tax report live, with the overview by asset category and direct mapping to KAP form lines. For those interested: it starts at around minute 38 in the video.
Who is this relevant for?
Anyone trading through a broker without automatic tax withholding. BubbleTax specialises in brokers running on the IBKR infrastructure, including Interactive Brokers directly as well as introducing brokers like WH SelfInvest.
If you trade with a traditional German bank that automatically withholds capital gains tax and issues an annual certificate, you don't need this.
Try it yourself
Upload your IBKR FlexQuery XML and see a free preview: Upload your IBKR data now.
Questions or feedback? Reach out via our feedback form or email us at info@bubbletax.de.
Disclaimer: This webinar and blog post are for informational purposes and do not constitute tax advice. BubbleTax is a calculation tool. For individual tax questions, please consult a tax advisor.