Knowledge
Clear background articles on the ideas behind my finance tools: asset classes, risk, financial independence, position sizing, company valuation and property investment.
Financial foundations
Retirement planning
A worked example shows how the partial exemption, saver allowance and Vorabpauschale change the cash you keep.
Asset classes & risk
How the S&P 500, Bitcoin and gold are compared on a shared euro basis, and what volatility, drawdown, Sharpe and Calmar actually tell you.
FIRE basics
The core formula, German tax details and a worked example you can follow.
FIRE basics
Where the best-known FIRE rule of thumb comes from, how it works and where its limits lie.
FIRE basics
Why averages can mislead and how to assess your personal risk more seriously.
Position sizing & risk
Position sizing & risk
The formula for an ideal stake when the odds are known, including its origin and a worked example.
Position sizing & risk
Why fixed stakes are usually suboptimal and how to tie position size to your edge.
Position sizing & risk
How to calculate the implied probability of odds and test whether you actually have an edge.
Company valuation
Company valuation
Turn the market price around to see what growth and margin a share price already assumes.
Company valuation
DCF valuation as of 29 May 2026, key risks, overvaluation and insider lock-up periods.
Company valuation
How to calculate company value and what the present value of future cash flows means.
Company valuation
How the cost of equity and debt fit together, and why WACC has such a strong effect on the result.
Company valuation
A worked example from the forecast phase through to the final company value.
Property investment
Property investment
Compare payments on €220,000 of remaining debt and check how much cash is left for setbacks.
Property investment
Gross and net yield, cash flow, ROE and the price multiplier, measured objectively rather than by gut feeling.
Property investment
How to include transfer tax, notary fees, agent fees and an amortising loan in the calculation.
Property investment
How rent growth, remaining debt, depreciation and the exit analysis develop over the holding period.
Economic concepts
Economic concepts
Use your spending weights to estimate personal inflation and compare purchasing power.
Economics
Keep the result fixed and make the input as small as necessary. Feasible versus optimal, constraints and common mistakes.
Economics
What are opportunity costs, and how do they shape everyday decisions?
Data analysis
Data analysis
Why low historical correlation cannot rule out losses in the same crisis.
Data analysis
Check provenance, units, duplicates, missing values and metrics before raw data becomes a chart.
Data analysis
A nutrition-optimizer example covering the pool, units, buildModel, solver, whole quantities and repair.