TLDR
The Australian Securities Exchange (ASX) 200 closed at 8,741.21 on 11 September, down 0.89%, its lowest since June, as Brent crude near US$110 a barrel pushed inflation fears back to the front. Australian CPI sits at 3.5%, above the Reserve Bank of Australia (RBA)'s target, and the next reading lands one day after the board meets on 29 September.
KEY TAKEAWAYS
The market reads the oil price and does not like it
The S&P/ASX 200 closed at 8,741.21 on 11 September 2026, down 0.89% for the session.[1] That puts the index at its lowest point since June, and the driver is not hard to find. Brent crude sat at US$109.51 a barrel on 9 September, closing in on US$110 for the first time in months.[2] Oil at that level moves directly into petrol prices, freight costs and, through those, into almost everything else.
The inflation picture the RBA will have to work with
Australian CPI rose 3.5% in the 12 months to July 2026, sitting above the RBA's 2 to 3% target band.[3] Two cost categories are doing most of the work, and neither is responding to the cash rate in any obvious way.
ABS head of price statistics Rachael McCririck said housing rose by 5.0 per cent in the 12 months to July, with new dwellings up 5.7% as builders passed on higher costs for materials and labour.[3] Those are supply-side pressures. A rate hold does not fix a shortage of tradies or timber.
Fuel told the same story. McCririck said automotive fuel prices rose 7.5 per cent in July after falling for three months in a row, driven by higher world oil prices and the partial unwinding of the federal government's fuel excise relief measures.[3] With Brent now back near US$110, July's jump looks less like a one-off and more like the start of a new leg up.
The RBA's timing problem
The RBA meets on 29 September. The next CPI release is scheduled for 30 September 2026, one day after the board sits down.[4] The board will set the cash rate without seeing the freshest read on the economy it is trying to cool, which is uncomfortable when oil is accelerating and the last CPI print was already above target.
Markets have drawn their own conclusion. ASX 30-day interbank cash rate futures settled on 18 August 2026 at 95.650, implying an average cash rate of 4.35%.[5] No cut is priced, so any business finalising a fourth-quarter budget is essentially working with 4.35% as the floor.
The RBA's September meeting falls on 29 September 2026, with the ABS CPI release following on 30 September.
SOURCES & CITATIONS
FREQUENTLY ASKED QUESTIONS
Why did the ASX 200 fall on 11 September 2026?
What is Australian inflation running at right now?
When does the RBA next meet, and what are markets expecting?
Why is the timing of the September CPI release significant?
James Dore is founder and editor of Prompt the Market and Strategy Director at Bushnote, a Sydney strategy, SEO and AI search agency. He has a background in strategy, media and financial services, and led consumer product marketing at MONEYME. He writes on AI search, answer engines, technology policy and media economics.
Important
This is general financial information only and does not constitute financial advice. It has not been prepared taking into account your objectives, financial situation or needs. Before making any financial decision, you should assess whether the information is appropriate for you and consider seeking advice from a licensed financial adviser.
