Australia’s Commodity Price Index Rises 1.4% in September, Up 15.5% From Year Ago

Australia’s commodity export prices rose again in September, with the Reserve Bank of Australia’s Index of Commodity Prices increasing 1.4% on a monthly average basis in Special Drawing Rights (SDR) terms. The index was 15.5% higher than a year earlier, extending a strong annual gain that has persisted through much of 2026.

The increase was broad rather than concentrated in one part of the basket. The RBA said its rural, non-rural and base metals subindices all rose during the month. Measured in Australian dollars, the overall index increased 1.0% in September and was 6.6% higher over the year, a smaller rise than in SDR terms because the currency denomination affects the reported movement.

In its September commodity-price release, the central bank said price increases over the past year were broadly based across most commodities. Iron ore, alumina and copper ore were the main exceptions, with their prices lower over the annual period covered by the release. The result is notable because iron ore remains by far the largest single component of the RBA basket.

Broad gains outweighed weakness in some major exports

The annual increase of 15.5% does not mean every Australian export commodity became more expensive. Instead, the headline index aggregates a basket in which each commodity receives a weight based on its importance in Australia’s commodity export values. That structure allows broad gains elsewhere in the basket to lift the overall measure even when a major export such as iron ore is down from a year earlier.

Under the weights introduced in April 2026, iron ore carries a 30.9% weight in the index. Metallurgical coal accounts for 11.4% and thermal coal for 8.5%, taking the combined bulk-commodity weight to 50.8%. Liquefied natural gas has a 16.3% weight, gold 9.8%, and the entire rural-commodities group 11.1%. Base metals account for a much smaller 3.6% share.

The composition was refreshed this year using average export values from the 2023/24 and 2024/25 financial years, and the index was rebased so that the 2024/25 average equals 100. Gold’s weight rose by 3.4 percentage points from the previous set of weights, the largest increase among individual commodities. Iron ore’s weight rose by 2.1 percentage points. Thermal coal, lithium, LNG and metallurgical coal all received lower weights than in the preceding year.

Those changes matter because the index is designed as a timely measure of prices received for commodities that are important to Australia’s export sector, not as an equal-weighted list of raw-material prices. The RBA describes the measure as a Laspeyres index, meaning recent price movements are combined using base-period weights tied to export values. The Bank updates the weights periodically so the basket continues to reflect shifts in the export mix.

The September release also changes the picture of the preceding month. The latest data show the index rising 0.3% in August in SDR terms, whereas the RBA’s original August release, published September 1, had estimated a 1.2% increase. The September figure should therefore be read against the latest 0.3% August estimate rather than the earlier preliminary number. Recent commodity-price estimates can change as fuller information becomes available.

Australia’s export outlook gives the index added economic weight

Commodity prices matter for Australia because resources and energy exports remain a major source of national export income. The Australian government’s June 2026 Resources and Energy Quarterly estimated that resource and energy export earnings rose to about A$405 billion in 2025/26 from A$385 billion in 2024/25. It forecast export earnings of about A$416 billion in 2026/27 before a gradual decline later in the outlook period.

The government report said the stronger near-term export outlook reflected higher-than-expected energy prices linked to Middle East supply disruptions and continuing strength in gold prices. It also projected gold export earnings to peak at A$73 billion in 2026/27, while iron ore was expected to remain Australia’s largest resource export over the forecast horizon.

That backdrop helps explain why the RBA’s commodity index can rise strongly even when iron ore itself is not contributing positively on a year-over-year basis. The basket is broad enough for gains across other commodities to offset weakness in selected products. The September release does not provide a commodity-by-commodity contribution table, so it does not support assigning the 1.4% monthly rise to any single export.

The difference between the SDR and Australian-dollar measures also deserves attention. The RBA publishes the index in several currency denominations because exchange-rate movements affect the value of internationally traded commodity prices when translated into local currency. In September, the 1.0% increase in Australian-dollar terms was smaller than the 1.4% SDR increase. Over 12 months, the gap was wider, with the Australian-dollar measure up 6.6% compared with 15.5% in SDR terms.

Spot-price measure showed a stronger September increase

A separate RBA measure based on spot prices for the major bulk commodities rose more sharply in September. Using spot prices for the bulk-commodity component, the index increased 3.3% in SDR terms during the month and was 17.7% higher than a year earlier. That compares with the 1.4% monthly and 15.5% annual increases in the headline index.

The two measures are not intended to be identical. The RBA’s methodology distinguishes between average export prices and spot-price benchmarks for bulk commodities such as iron ore and coal. Average export prices can reflect both spot and contract pricing as well as differences in the quality mix of exports. Spot benchmarks, by contrast, track current market prices for defined specifications. That can produce periods in which the spot-price measure moves faster or more sharply than the broader export-price index.

The RBA said the most recent estimates for iron ore, coking coal, thermal coal and LNG continue to rely on preliminary export-price estimates based on market information. That means the latest monthly readings are useful as a timely indicator but are not necessarily the final values that will remain in the historical series.