The Australian Bureau of Statistics (ABS) will publish its Consumer Price Index for September 2026 at 11.30am AEDT on Wednesday 28 October, the last major inflation reading before the Reserve Bank of Australia (RBA) decides on interest rates on Tuesday 3 November, Melbourne Cup Day.
The release matters to borrowers because the RBA has already lifted the cash rate four times in 2026, most recently by 25 basis points to 4.60% in September, according to CommBank. The RBA’s target band for inflation is 2% to 3%, Australian Broker reported. On 25 October, markets were pricing an 80% chance of another rate rise by December, Capital Brief reported.
Every figure below is a forecast made ahead of the release, and each is attributed to the economists who made it.
What CommBank Expects
CommBank’s economists set out their forecasts on 22 October. For the September quarter, they expect the trimmed mean, the RBA’s preferred underlying measure, to rise 1.0%, with the annual rate at 3.6%. They expect headline inflation of 1.3% for the quarter and 3.9% over the year to the September quarter.
The bank has made a separate forecast for the monthly measure. For the month of September, it expects annual headline inflation to rise to 4.2%, up from 4.0% in August, with the annual trimmed mean unchanged at 3.6%. The 3.9% and 4.2% figures are two different CommBank forecasts: the first is for the year to the September quarter, the second is the annual rate for the month of September.
If CommBank is right, the September quarter would be the fifth in a row with trimmed mean inflation between 0.8% and 1.0%, above the RBA’s August forecast of 0.8%.
Other Forecasts
The Bloomberg consensus is for trimmed mean inflation of 1% for the quarter and 3.6% over the year, Capital Brief reported on 25 October. AMP’s Diana Mousina expects headline inflation of 1.2% for the quarter and 3.9% over the year, with trimmed mean at 1% and 3.6%.
Ms Mousina said that “activity is slowing and, after four rate increases, including one just last month, it makes sense to give those hikes time to work through the economy”, Capital Brief reported.
Fuel, Services and Rents
CommBank forecasts petrol prices up 9.8% in September after a 14.8% rise in August, leaving them about 24% higher over the year. That would add around 0.3 percentage points to the monthly headline rise, the bank said.
The bank expects market services inflation to rise from 4.1% to 4.3%. It has new dwelling prices up 0.2% in September, with the annual rate easing from 5.4% to 4.9%, and rents rising at around 3.5% a year. On the wider housing market, we reported on 1 October that Australian house prices had fallen for a sixth straight month.
The RBA Backdrop
RBA deputy governor Andrew Hauser said on Wednesday 21 October that the inflation outlook “looks materially worse” than earlier estimates, Australian Broker reported. The outlet also reported him using the phrase “the central banker’s nightmare.” After his comments, market-implied odds of a rate rise in November jumped from about 24% to 56%, according to CommBank.
We covered the last cutting cycle when the RBA cut rates to 3.85% in May 2025.
CommBank’s baseline is still a hold on 3 November, but the bank calls the meeting “live”. “While our baseline remains for the RBA to leave the cash rate unchanged, the decision will depend heavily on the outcome and composition of next week’s CPI print,” CommBank senior economist Trent Saunders said.
“We expect underlying inflation to improve beyond the September quarter, but only gradually, with a risk that progress may be too slow for the RBA,” Mr Saunders said.
The Number to Watch at 11.30am
The trimmed mean for the September quarter is the figure closest to the RBA’s thinking, because it is the bank’s preferred underlying measure. CommBank, AMP and the Bloomberg consensus all have it at 1% for the quarter, against the RBA’s August forecast of 0.8%.
The ABS release is at 11.30am AEDT on Wednesday 28 October, and the RBA’s decision follows on Tuesday 3 November.
More economic coverage is in our Financial section.
Sources: Australian Bureau of Statistics, “Release calendar, October 2026: Consumer Price Index, Australia, September 2026” (https://www.abs.gov.au/release-calendar/future-releases-calendar/202610/rcc_economy); CommBank Newsroom, “September data will keep inflation pressure on RBA: CommBank economists”, 22 October 2026 (https://www.commbank.com.au/articles/newsroom/2026/10/inflation-cpi-rba-interest-rates-november.html); Capital Brief, “Make-or-break for rate hike: Markets brace for inflation scorecard”, 25 October 2026 (https://www.capitalbrief.com/article/make-or-break-for-rate-hike-markets-brace-for-inflation-scorecard-fd5a0e5b-382c-4816-9fe4-8d8f63e3f04d/); Australian Broker, “RBA rate hike fears reignite as inflation outlook worsens”, 22 October 2026 (https://www.brokernews.com.au/news/breaking-news/rba-rate-hike-fears-reignite-as-inflation-outlook-worsens-290195.aspx)
Photo: Danausi, public domain, via Wikimedia Commons.
The Reserve Bank of Australia’s head office tower in Martin Place, Sydney, pictured in November 2008.
