AUD, CAD, NZD: Commodity Currency Linkage Mechanics

Commodity currencies move with their dominant export. But the linkage is not equal across AUD, CAD, and NZD — each pair has a different commodity driver, a different beta, and a different lag. Trading them blindly as "risk-on" misses the structural edge.

The export-to-FX map

• AUD — iron ore. Iron ore is roughly 20% of Australian goods exports. AUD/USD tracks iron ore (USD/tonne, Singapore SGX contract) with a 60-day correlation often above +0.7.
• CAD — WTI crude. Oil is about 15% of Canadian exports. USD/CAD correlates inversely with WTI (WTI up, USD/CAD down) at roughly -0.5 to -0.7 on a 60-day basis.
• NZD — whole milk powder. Dairy is roughly 25% of NZ exports. NZD/USD reacts to GlobalDairyTrade auction results, which print every two weeks; reaction can move NZD 30–60 pips on a 5%+ price swing.

Quantifying the beta

Run a 60-day regression of daily FX returns on the commodity return. AUD/USD beta to iron ore typically sits near 0.25–0.35. USD/CAD beta to WTI is similar in magnitude but negative-signed. NZD beta to dairy is noisier because auctions are discrete. When beta drops below 0.15, the linkage is breaking — usually because rate differentials or risk sentiment have taken over.

Trade filters

Use the commodity signal as a confirmation filter, not a standalone trigger. A long AUD/USD setup near support has higher expected value when iron ore is making a 5-day high. A USD/CAD long is weaker when WTI is breaking out the same session. If FX diverges from the commodity by more than two days, the divergence usually resolves back toward the commodity, not away from it.

When the linkage breaks

Three breaks matter: central bank divergence (RBA vs Fed surprises override commodities), risk-off episodes (VIX above 30 drags all three lower regardless of commodity strength), and terms-of-trade shifts (commodity falls but currency holds on rate-hike expectations).

The bottom line

AUD follows iron ore, CAD follows WTI, NZD follows dairy — with pair-specific betas and lags. Track the 60-day correlation and beta; trade FX in the direction of the underlying commodity, and stand aside when correlation drops below 0.5 or when VIX is above 30. The commodity is the fundamental anchor; the FX pair is the derivative.