Two-Asset Sandbox

The intuition behind the engine: capital weight is not risk weight.

Two-asset case
The point the workbook makes in miniature: equal dollars is not equal risk. Adjust the two volatilities and the correlation, then watch how much of the portfolio's risk the more volatile asset carries.
SizingCapital ACapital BRisk share ARisk share BPortfolio vol
Equal capital (50 / 50)50.00%50.00%10.00%90.00%9.49%
Inverse volatility75.00%25.00%50.00%50.00%6.36%
Equal risk contribution75.00%25.00%50.00%50.00%6.36%
At a 50/50 split the more volatile asset carries 90.0% of the risk. Sizing for equal risk moves capital to 75.0% / 25.0% and lowers portfolio volatility from 9.49% to 6.36%.
Correlation sweep
The same two assets across every possible correlation, from perfectly hedging (−1) to perfectly aligned (+1). The diversification benefit is the gap between the lines — it disappears entirely on the right-hand edge.

The dashed vertical line marks the correlation selected above. Where the risk-share line sits above 50%, equal dollars is quietly handing the volatile asset the majority of the portfolio's risk — which is exactly what the risk engine corrects for on a real sleeve.