Self-service tool · No tax advisory/ case review · Results may vary – please verify
About KapitalTax
Last updated: March 13, 2026
KapitalTax helps to prepare data from Interactive Brokers in a structured way for the German tax return. Our focus is on transparent reports for topics such as FIFO, advance lump sum, options, and creditable foreign withholding tax.
While Interactive Brokers provides extensive trading and account data, this data often cannot be directly used for the German tax return. This is exactly where KapitalTax comes in: with the goal of transforming complex IBKR data into a form that is practically usable for further tax processing.
Our Team
Behind KapitalTax is an interdisciplinary team of tax expertise, software development, and product design.
Our goal is to prepare complex IBKR data in a transparent and usable way for the German tax context.
Julian
Tax Topics, Website & Output Structure
Julian holds a PhD in Physics and has been using Interactive Brokers since 2018. From his own experience, he is well aware of the practical challenges involved in preparing transaction data for the German tax return. At KapitalTax, he is responsible for analyzing relevant legal texts, tax logic, the content structure of the website, and the design of tax-relevant reports.
Felix
Backend · Technical Implementation of Tax Logic
Felix is pursuing a PhD in Computer Science and has spent about a year and a half working in algorithmic crypto trading in the DeFi space in the UK. At KapitalTax, he implements the tax-relevant functions and calculation logic in the backend. His focus is on translating complex tax requirements into reliable, transparent, and scalable processes within the application.
Victor
Frontend & UX · App and User Experience
Victor is pursuing a PhD in Physics and is responsible for the frontend and user experience at KapitalTax. His focus is on translating complex tax topics into a clear, understandable, and user-friendly interface. He works to ensure that users can quickly get an overview even with extensive IBKR data and use the reports transparently.
Why We Built KapitalTax
Interactive Brokers is a powerful broker for many investors – especially for international securities, active strategies, and more complex portfolios. At the same time, it quickly becomes clear with the German tax return that powerful trading data does not yet mean tax-usable preparation.
This was exactly our starting point for KapitalTax. Many users face the same challenge: While German brokers provide a ready-made tax certificate, data from Interactive Brokers often has to be laboriously compiled from transactions, distributions, foreign currencies, and other portfolio events for the German tax return.
We built KapitalTax to close this gap. Our goal is to prepare tax-relevant information from IBKR data transparently and transfer it into a structure that users can practically work with. We're not aiming for a black-box solution, but rather a clear, transparent, and understandable preparation for the German tax context.
How We Work
KapitalTax combines tax expertise, technical implementation, and clear product design. Our goal is to prepare data from Interactive Brokers for the German tax context so that it becomes transparent, understandable, and practically usable.
We value:
- Transparent logic instead of a black box
- Structured reports instead of confusing raw data
- Focus on real IBKR use cases like FIFO, advance lump sum, options, and withholding tax
KapitalTax assists in preparing IBKR data but does not replace individual tax advice.
What KapitalTax Does – and What It Doesn't
KapitalTax supports the structured preparation of Interactive Brokers data for the German tax context. Our focus is on transparent reports on topics such as FIFO, advance lump sum, options, and creditable foreign withholding tax.
KapitalTax works on a use-case basis. This means: We focus on the tax scenarios that many users actually encounter in practice and implement them specifically in the application.
However, KapitalTax does not offer individual tax or legal advice and does not replace a personal review in individual cases. Especially in the tax area, in addition to common practical scenarios, there are also numerous rare or very special cases. Such cases are not automatically covered in KapitalTax if no corresponding use case has been implemented in the application.
Our goal is to make IBKR data more understandable, structured, and usable for further tax processing – not to process every conceivable special case.
Further Detail Pages / Methodology
For important tax topics related to Interactive Brokers, we have built dedicated detail pages. There we explain key backgrounds, practical case scenarios, and the logic by which KapitalTax prepares relevant data in a structured way.
Learn more on our pages about:
Interactive Brokers Tax Return in Germany
Overview of the tax preparation of IBKR data
Advance Lump Sum at Interactive Brokers
ETFs, funds, partial exemption and KAP-INV
Options at Interactive Brokers
Option premiums, assignment, expiration and cash settlement
Withholding Tax at Interactive Brokers
DTA logic, 25% cap and partial exemption
Contact
Do you have questions about KapitalTax or want to reach us directly? Feel free to use our contact form or write us an email.
Please note: KapitalTax assists in preparing IBKR data but does not offer individual case reviews or individual tax or legal advice.
Published on: March 13, 2026