Interactive Brokers Tax Report
Turns an Interactive Brokers transaction log into a tax report that follows German tax rules.
- Go
- TypeScript
Simon Johannes Jähn · M.Sc. Business Administration · Bremen
Turning data into decisions that hold up under uncertainty — working where machine learning, finance and risk meet.
About
I'm an M.Sc. Business Administration student at the University of Bremen, where I also finished my B.Sc. in Business IT with a final grade of 1.18.
I'm a working student in Credit Risk Controlling at Die Sparkasse Bremen. I started in the CRCU-PD and now work mainly in the Internal Validation Unit (IVU).
- Based in
- Bremen, Germany
- Studying
- M.Sc. Business Administration
- Working as
- Working Student, Credit Risk Controlling
- Focused on
- Machine learning, finance & risk
Experience & Education
- Experience
Working Student — Credit Risk Controlling
Die Sparkasse Bremen (Bremen, Germany)
Since 11/2025
- CRCU-PD, later IVU
- Education
M.Sc. Business Administration
University of Bremen (Bremen, Germany)
Since 10/2025
Focus: Finance, Accounting
- Inflation forecasting
- Risk-based portfolio optimisation
- Education
B.Sc. Business IT
University of Bremen (Bremen, Germany)
10/2022 — 09/2025
Final grade 1.18 (≈ 3.8/4.0 GPA)
Focus: Computational Finance
- Forecasting asset returns with machine learning
Projects
Risk-Based Portfolio Optimization
Builds risk-based portfolios, forecasting volatility and correlations with GARCH and DCC-GARCH models.
- Python
- GARCH
- DCC-GARCH
Directional Bitcoin Forecast
Predicts the direction of Bitcoin returns using LSTM networks and gradient-boosted trees.
- Python
- LSTM
- XGBoost
Focus
Machine Learning
Building and validating models that learn from data — from feature engineering through to reading what the output actually means.
Finance
Quantitative approaches to valuation, portfolio construction, and the mechanics of how markets behave.
Risk
Measuring and controlling credit and financial risk — putting numbers on uncertainty without hiding it.
Skills & Languages
- Programming
- Python, Java, Go, SQL
- Machine learning
- scikit-learn, PyTorch, TensorFlow
- Tools
- Git, LaTeX
- Languages
- German (native), English (professional working proficiency)