An iron ore cargo leaves Port Hedland bound for a Chinese steel mill. Somewhere in that transaction, dollars have to become Australian dollars, and multiply it by the volume Australia ships and you have a structural bid for the currency that has nothing to do with interest rates or positioning. That is the honest core of the commodity currency idea.
The trouble starts when traders take the idea further than it goes. AUD is not a proxy for iron ore in any tick-by-tick sense. The export flow is slow and largely hedged. What moves the currency intraday is expectation about that flow, filtered through rate differentials and general appetite for risk.
Three currencies, three different exports
Grouping AUD, CAD and NZD together is convenient and slightly lazy, because the underlying commodities behave nothing alike.
Australia sells bulk minerals: iron ore, coal, liquefied natural gas, plus a large services and education relationship with Asia. Demand is concentrated in China, and specifically in Chinese construction and steel output. When Beijing announces infrastructure spending, the Aussie usually notices before the ore price does.
Canada sells oil, and it sells most of it to the United States at a discount to the global benchmark because of pipeline capacity. That is why USD/CAD has an oil relationship rather than an oil identity, and why the pair also carries a heavy dose of pure US macro. We went through the mechanics in oil and the Canadian dollar, and the summary is that CAD reacts to oil most reliably when the oil move is driven by demand rather than by a supply shock.
New Zealand sells food: dairy above all, plus meat and horticulture. The export base is smaller and less diversified, and the currency is less liquid than the other two. That combination makes NZD the most prone to sharp moves on thin books, especially during the hours when neither London nor New York is fully open. The session pattern is worth knowing before sizing anything, and it is covered in the trading sessions guide.
Rates still lead, most of the time
Over a week or a month, interest rate expectations usually explain more of the movement than the commodity does. All three central banks target inflation and all three publish rate paths that the market prices in advance. A hawkish surprise from the Reserve Bank of Australia moves AUD more sharply than a comparable move in iron ore.
That is also why these currencies feature so heavily in carry positioning. When AUD or NZD rates sit above the funding currency's, the pair attracts carry trade flows, which build slowly and unwind violently. The unwind is the risk that catches people: a position that paid a small daily credit for months can give back a quarter of that in a single session when risk appetite turns.
The correlation that traps beginners
AUD/USD and NZD/USD move together often enough that a trader long both feels diversified while holding roughly one position at double size. The same trap exists between AUD/USD and short USD/CAD, though the link is weaker.
Correlation is not constant. It rises during stress, which is exactly when the extra concentration hurts. The practical fix is to compute exposure by currency rather than by pair, and to treat two highly correlated positions as one for sizing purposes. The method is in currency correlations, and the sizing consequence is in lots and position sizes.
All three are treated as risk-on currencies, so they tend to fall together when equities fall and safe haven flows pick up. If your portfolio already leans long risk, adding long AUD is not diversification. It is more of the same trade wearing a different ticker.
What actually moves them, in order
Practically, the release calendar for these three is short and worth knowing by heart. Australian employment and quarterly inflation, RBA decisions and minutes, and Chinese activity data including industrial production and property indicators. Canadian employment and inflation, Bank of Canada decisions, and US data, which for USD/CAD is often the larger driver of the two. New Zealand quarterly inflation and RBNZ decisions, plus the dairy auction results that come in through the month.
Notice that half of the list is foreign. For CAD, US releases frequently outweigh Canadian ones because the pair contains the dollar and because the Canadian economy is tied to the American cycle. For AUD, Chinese data outweighs a lot of domestic data. Trading these currencies means watching two calendars, not one, and the calendar guide explains how to keep both in view without drowning.
Practical points for sizing and holding
Spreads on AUD/USD and USD/CAD are competitive at most brokers, while NZD/USD and the crosses are wider, and all of them widen around the daily rollover. If you hold overnight, the swap is a real component of the return rather than a rounding error, positive or negative depending on direction and rate differentials.
Gaps matter too. These currencies open the week first, so a weekend headline out of Beijing or a Sunday political development lands on AUD and NZD before anything else can react. Anyone holding over a weekend should size for a gap through the stop rather than assuming the stop fills at its level, a point covered in weekend gaps.
Leveraged trading in any of these carries a high risk of loss, and the commodity link does not make direction predictable. It gives you a framework for why a move might be happening, which is useful for staying in a good trade and for getting out of one whose reason has disappeared. That is all a framework can honestly do.
"People trade the Aussie as if it were a chart of iron ore. It is closer to a chart of what traders believe about Chinese construction, which is a different thing and it turns faster."
— Roman Onta, Executive Director, SINGUARD
Key Takeaways
- AUD, CAD and NZD track different exports: bulk minerals to China, oil to the United States, and dairy respectively, so grouping them hides more than it explains.
- Interest rate expectations usually explain more weekly movement than the underlying commodity does, which is why these currencies dominate carry positioning.
- AUD/USD and NZD/USD are closely correlated and the correlation tightens under stress, so holding both is concentration rather than diversification.
- Foreign data often outweighs domestic data: Chinese activity for AUD, US releases for CAD.
Frequently Asked Questions
Why is the Australian dollar called a commodity currency?
Australia's exports are heavily weighted towards bulk commodities such as iron ore, coal and liquefied natural gas, mostly sold into Asia. Demand for those exports creates demand for Australian dollars, so the currency tends to track expectations about commodity demand, particularly from China.
Does USD/CAD follow the oil price?
There is a relationship, but it is conditional. CAD tends to respond most clearly when oil moves on demand expectations, and less when the move comes from a supply disruption. USD/CAD also contains the US dollar, so American data frequently drives the pair more than Canadian data does.
Is trading AUD and NZD together a diversified position?
Usually not. The two pairs are strongly correlated and the correlation tends to rise during market stress. Traders holding both are generally carrying one directional exposure at roughly double size, which is why exposure should be measured by currency rather than by pair.
About the Author
Roman Onta is an Executive Director at SINGUARD. He builds the Prop Firm CRM, the Broker CRM, Scalegram and CopySignals side by side with his brother Alex Onta, and he helped on the design of eTrader, the division Alex built and leads. His ground is worldwide payment processing, AML compliance and the corporate structures brokers are built on, work the two of them carry together, shaped by executive roles in the UAE and international corporates. He lives and works in Dubai for most of the year. Meet the executive duo leading Singuard's five divisions.