ABS CPI September 2026: Why Inflation Hit 4.3%, and What It Means for Property Investors

Published 31 October 2026 · Primary source: ABS Consumer Price Index, Australia, September 2026 (released 28 October 2026), including the September-quarter series · Bank forecasts and market pricing as reported on 28–29 October 2026 · Full data dates in the methodology box

At a glance

Source: ABS, Consumer Price Index, Australia, September 2026 (released 28 October 2026), Tables 1, 3, 6 and Appendix 1a. The RBA forecast comparison is as reported by AAP (InDaily, 29 October 2026).

The ABS CPI September 2026 release on Wednesday 28 October carried two numbers that pointed different ways. The monthly headline rose to 4.3%, mostly because petrol jumped. The quarterly trimmed mean, which strips out the biggest price moves in both directions, rose 1.0%. That second figure is the one the RBA gives most weight to when it judges persistent pressure, and it came in above the Bank's August path. The quarterly 1.0% matched economists' expectations, though the annual 3.7% and the 4.3% headline were each a tenth above consensus (NAB). The bigger gap was against the RBA's August forecast; NAB judged the result "likely close to their most recent nowcast", which fits the warnings RBA officials gave beforehand (NAB, 28 October). By the end of the day, weighing the print together with the Governor's Senate Estimates testimony, all four major banks expected a rise to 4.85% on 3 November.

This article sets the rate call to one side and works through the release line by line, asking which parts reach an investor's rent, holding costs and build costs. The previous edition, our July CPI analysis, covered the print that reopened the hike debate in August, and the last quarterly comparison is in our June CPI analysis.

What did the ABS CPI September 2026 release show?

Since the October 2025 reference month, the complete monthly CPI has been Australia's primary inflation measure. The quarterly series continue in the March, June, September and December releases, and the RBA still forecasts the quarterly trimmed mean. The two can differ because quarterly figures compare three-month averages.

Monthly and quarterly measures

Source: ABS, Consumer Price Index, Australia, September 2026, Tables 1 and 6, Appendix 1a (quarterly trimmed mean and weighted median, pre-October 2025 methods) and Table 17 (headline, original). On the Table 17 index the original-terms annual headline for the quarter is 3.9% (103.64 against 99.73), our calculation.

The month's most useful line is the gap between "excluding volatile items" (+0.5%) and "excluding volatile items and holiday travel" (0.0%). Take out fuel, fresh food and holiday travel, which rose 7.6% in the month (domestic travel 8.0%, ABS), and prices were flat in September.

The 2026 scoreboard: how September fits the year

Source: ABS, Consumer Price Index, Australia, September 2026, Tables 1 and 6 (current vintage: seasonal revisions moved the April, May and August trimmed-mean readings by 0.1 point from first publication); RBA cash rate target history.

Source: ABS, Consumer Price Index, Australia, September 2026, Appendix 1a (pre-October 2025 methods).

The headline swings with fuel and electricity; the core stopped improving in the autumn and is now edging up. On our calculation from the ABS index, the September quarter's 1.0% is an annualised pace of about 4.0%, and the six months to September annualise to about 3.7% (Appendix 1a: 147.5875 in September, 146.13 in June, 144.928 in March). The monthly trimmed mean rose 0.5%, 0.2% and 0.3% in July, August and September, also about 4.0% annualised. Three cuts of the same data put current underlying inflation at roughly 3.7–4.0%.

Why did inflation jump to 4.3%? Fuel and electricity versus the rest

Contributions to annual inflation (percentage points)

Source: ABS, Consumer Price Index, Australia, September 2026, Tables 4 and 6 (contributions to the all groups annual change; data downloads). The change column is calculated from unrounded ABS values (electricity 0.3154 to 0.3034), so it can differ from the difference between the rounded columns. The rows are nested, not additive: fuel is part of "all groups excluding housing" and electricity is part of the housing group. Housing (1.14) plus all groups excluding housing (3.20) gives the 4.34-point headline.

Fuel. Automotive fuel rose 9.4% in September and 23.6% over the year. In June it was 7.3% cheaper than a year earlier, helped by the federal excise reduction that ended in early August. That swing is the largest single reason annual inflation rose from 3.5% to 4.3% in two months. Fuel reaches a property investor mainly through the rate path. In our view, the RBA can look through a one-off fuel shock only if it doesn't feed into wider price-setting and expectations. Deputy Governor Andrew Hauser said on 21 October that the RBA's business survey with Macquarie University "shows that there is an increasing share of businesses who are thinking that maybe three to three and a half per cent is the new normal" (RBA transcript), which is why a fuel-led headline still weighs on the decision.

Electricity. Prices rose 12.8% over the year, "largely due to the ending of Commonwealth electricity rebates over the year" (ABS). Rebate timing has distorted this line all year: 22.4% in June, 6.1% in July, 13.2% in August. For most landlords electricity is a tenant cost.

What's left. Take fuel and electricity out and about 3.3 points of the 4.3% remain (4.34 less 1.07, our calculation from unrounded ABS contributions). That is a residual contribution to the headline, not a measure of underlying inflation, so it shouldn't be read against the 2–3% target band.

Is underlying inflation still running above the RBA's forecast?

The RBA's August Statement on Monetary Policy forecast trimmed mean inflation of 3.3% in December 2026, 3.0% in June 2027 and 2.6% in December 2027, and said underlying inflation would "remain above 3 per cent until mid-2027" (RBA SMP August 2026, Table 3.1). The table doesn't print a September-quarter figure; AAP reported the implied path as 0.8% for the quarter (via InDaily, 29 October).

What December would need to show (our arithmetic)

Source: our calculation from the ABS trimmed-mean index (Appendix 1a: 143.7126 in December 2025, 147.5875 in September 2026); RBA Statement on Monetary Policy, August 2026. A 3.3% outcome needs about 0.54–0.64%, depending on rounding.

None of the seven quarters since March 2025 has been as low as 0.6%; the smallest were 0.7% in the March and June quarters of 2025 (ABS Appendix 1a). The RBA has signalled the same conclusion. Governor Michele Bullock told Senate Estimates on 28 October that "inflation will therefore likely be higher than was our base case in August" (RBA, opening statement), and Hauser said on 21 October that "the inflation outlook looks materially worse than we projected in the August report" (RBA transcript, 21 October). New forecasts arrive with the 3 November Statement on Monetary Policy.

Services: high, but September's jump was mostly travel. Services inflation was 4.1% and non-tradables, prices set mainly by domestic conditions, 4.5%. The ABS measure of market services excluding volatile items rose to 4.0% from 3.3% in August, but that jump was largely the 7.6% rise in holiday travel, and NAB described market services components as "generally benign in the September month" (NAB, 28 October). Market goods slowed to 2.7% from 3.1%. Deloitte Access Economics partner Stephen Smith said price growth in parts of the economy "not directly exposed to the effects of the Middle East conflict remains uncomfortably high" (AAP via InDaily, 29 October). The persistence signal is in the quarterly trimmed mean rather than one month's services figure.

The labour market is the counterweight. The seasonally adjusted unemployment rate rose 0.1 point to 4.7% in September (4.4% in June; trend 4.6%), and employment fell by 39,300 (ABS Labour Force, 15 October), against the RBA's August forecast of 4.5% by December.

For landlords, a weaker job market works through tenants as well as rates: job losses and slower wage growth reduce what tenants can pay and can push vacancy higher. That tends to show first where vacancy is already above a year ago, most clearly in Sydney, Melbourne and Canberra on SQM Research's September figures. With vacancy below 2% in every capital and below 1% in five, the more likely early effects are smaller increases at renewal and longer letting times rather than outright falls.

The housing breakdown: rents, new dwellings and landlord costs

Rents: why the CPI runs behind asking rents

CPI rents rose 3.6% over the year to September, unchanged since May, and 0.2% in the month (0.3% excluding the September indexation of Commonwealth Rent Assistance). In the quarterly series they rose 1.0% in the September quarter, up from 0.8% in June. Asking rents are running faster: SQM Research's rose 7.6% nationally and 5.1% across the capitals over the year to the week ending 12 October, and Cotality's rent index rose 5.5% over the year, though only 0.5% in the September quarter, its smallest quarterly rise since December 2024 (Cotality Monthly Housing Chart Pack, October 2026).

The series measure different things:

• The CPI measures rents actually paid by new and existing tenants in private and government rentals in the eight capitals, net of Rent Assistance. The ABS tracks a matched sample of the same properties over time and adds new properties to the sample periodically. In any month most tenants in the sample are mid-lease, so their rent hasn't changed, which is why the CPI moves more slowly than listings.
• Asking rents measure new listings, the price advertised for a lease signed today. They move first, in both directions.
• Compare capitals with capitals. SQM's 7.6% national figure includes regional markets the CPI doesn't cover. Against SQM's 5.1% capital-city average, the gap is about 1.5 points.

Source: ABS, Consumer Price Index, Australia, September 2026, Table 11 (rents by capital city); SQM Research, National Vacancy Rates, September 2026 (released 13 October 2026; asking rents for the week ending 12 October, combined houses and units). Different measures, shown side by side; see the methodology box.

The widest gaps are in Darwin (7.4 points) and Hobart (6.3 points), small markets with vacancy at or below 0.6%, where asking rents have run well ahead of existing leases. Among the larger capitals, Melbourne (3.2 points) and Canberra (3.4 points) have wide gaps and, with Sydney, the highest vacancy. There, listings are softening: SQM Research said the rise in national vacancy to 1.4% suggests "we are beginning to see a gradual easing in rental conditions, led by Sydney and Melbourne" (SQM Research, September 2026). In Perth, CPI rents are rising slightly faster than asking rents, which on our reading suggests that city's catch-up has largely happened.

Neither national figure tells an individual landlord what their own property can achieve. The city table shows asking-rent growth ranging from 4.5% to 13.9%, and in SQM's September data national house rents rose 1.6% over the month while unit rents fell 1.6%, with unit rents down in seven of the eight capitals. Our vacancy rate tracker carries SQM's monthly city figures.

New dwellings: builders start discounting

New-dwelling purchase prices for owner-occupiers rose 4.7% over the year, down from 5.4% in August and 5.8% in June, and were unchanged in the month. The ABS says the annual rise was "driven by project home builders raising base prices to pass through higher labour and materials costs over the year", while the flat month reflected "some builders increasing discounts and promotional offers in response to slowing new demand".

This line isn't a measure of what investors pay for property. The CPI's new-dwelling series covers owner-occupiers' purchases of new homes and excludes land. Purchases of existing homes are outside the CPI altogether, and so are mortgage interest costs. For prices, see Cotality's and PropTrack's indexes, and for interest, our RBA November preview.

Costs are still rising. Cotality's Cordell Construction Cost Index rose 1.0% in the September quarter and 3.2% over the year, up from 2.8% (Cotality, 21 October 2026), with Western Australia leading at 1.1% for the quarter. With costs rising about 3% a year and selling prices slowing toward that pace, we infer that builder margins are likely under pressure, which would be consistent with more incentives for buyers of house-and-land and off-the-plan stock. Cordell measures construction costs, not builder profitability.

Landlord cost lines: most are rising faster than CPI rents

Source: ABS, Consumer Price Index, Australia, September 2026, Table 3 (expenditure classes). "Usually paid by" is a general description; it depends on the lease and state law. The insurance figure is the ABS's broad insurance class; individual landlord insurance premiums can rise at a different rate.

A worked illustration (hypothetical). Take non-interest holding costs of $8,000 a year: council rates $2,200, water service charges $1,100, insurance $2,000 and maintenance $2,700. At each line's September annual rate they rise by $123, $112, $108 and $92, a total of $435 (5.4%). If the property rents for $600 a week ($31,200 a year), a rise in line with CPI rents (3.6%) adds $1,123 of income, and one in line with SQM's capital-city asking rents (5.1%) adds $1,591. Either covers the cost increase. These are hypothetical gross increases, not ones any property is guaranteed to achieve. The comparison also leaves out land tax, strata, property management, vacancy and, above all, interest, by far the largest holding cost; our RBA November preview and cash flow calculator cover it.

Source: our illustration using ABS CPI annual rates for September 2026 and a hypothetical cost mix; your own bills will differ.

In percentage terms these bills are rising faster than rent, but on a typical cost mix, rent rising at the CPI pace still covers the dollar increase. The margin narrows where rates, strata and insurance take a large share of the rent, as in low-rent units and high-strata buildings, and above all where interest rises.

These costs are generally deductible against rental income, subject to ATO rules; our investment property tax deductions guide covers which and when.

Inflation by capital city

Source: ABS, Consumer Price Index, Australia, September 2026, Table 1 (capital cities).

The pattern lines up loosely with the rent table above. Melbourne and Sydney have the lowest measured inflation, vacancy among the highest of the capitals (with Canberra, SQM) and the largest annual price falls (Sydney −7.0%, Melbourne −6.2%, Cotality HVI, September); Hobart, Darwin and Adelaide have vacancy at or below 0.6% and higher inflation. City CPI covers far more than housing, so the link is loose, says nothing about cause and isn't a buy signal. National inflation can rise even where local demand is softening, so a Sydney or Melbourne investor shouldn't count on local weakness to hold the cash rate down. Where rental demand is strongest, rent growth has more support, one reason smaller capitals and regional markets feature heavily in yield screens such as our Top 10 Suburbs October 2026 edition.

What the September CPI means for the 3 November RBA decision

Source: each bank's own note or newsroom article, linked; ANZ's call as reported by The Adviser, 28 October 2026; market pricing from the ASX RBA Rate Tracker, daily closes from one source. Implied yields are the market's expected average cash rate for the month, not a forecast or a guarantee.

A rise would take the cash rate to its highest level since 2008 (RBA cash rate history) and make five rises in 2026. CBA had said in September that a quarterly trimmed mean of 1% or more "could nevertheless put another increase on the table", and the result was 1.0%. What 4.85% means for repayments, borrowing capacity and interest cover is in our companion piece, RBA November 2026 Rate Decision: A Hike to 4.85% Is Now the Base Case.

What it means for property investors: our analysis

Inflation reaches an investor through operating costs, borrowing costs, building and replacement costs, and tenants' budgets. The next RBA decision acts directly on only the second.

1. Rates are likely to stay higher for longer. CBA has cuts pencilled in for August and November 2027, conditional on progress on inflation. Our planning assumption is more cautious: don't budget on a 2027 cut until underlying inflation is clearly heading below 3%, and stress-test holdings and purchases on that basis.

2. Price rent from your street, not the national figure. With vacancy above year-ago levels, most clearly in Sydney, Melbourne and Canberra, base rent reviews on current comparable listings and days on market, not last year's increase. Our rental yield calculator works at today's asking rent.

3. Budget holding costs at their own rates. Council rates, water and insurance are running at 5–10%. For a negatively geared established property acquired after 7:30pm on 12 May 2026, the owner funds the full pre-tax shortfall from 1 July 2027 with no offset against salary; the loss is quarantined and carried forward against residential rental income and gains. Our Sell or Hold Planner models how the reform treats each property you already own.

4. New-build pricing is softening at the margin. Builders' discounts and Cordell's 3.2% cost growth point to less pricing power than a year ago. For investors weighing new against established stock under the 2027 rules, that's negotiating room. Our negative gearing transition plan covers which new builds qualify.

5. Judge the next releases on the core. If oil eases, the headline could fall quickly, as it did between March and July, but that is unlikely to change the RBA's view while the trimmed mean runs near 1% a quarter. October will be noisy in the other direction: NAB expects fuel prices to "rise another 7% in October", and says the end of card surcharging "will also support measured inflation in the October month, muddying the underlying inflation signal" (NAB, 28 October).

The Bottom Line

In the ABS CPI September 2026 release, fuel lifted the headline to 4.3%, but the quarterly trimmed mean is what is pushing the RBA toward a fifth rise. That leaves investors with three decisions:

1. Stress-test your financing at your current rate plus about 0.75 points (Tuesday's expected rise, the further rise Westpac flags for February, and a margin; our RBA November preview sets out the basis), and don't budget on a 2027 cut until underlying inflation is clearly heading below 3%.
2. Budget non-interest holding costs at their own rates, 5–10% for rates, water and insurance, not at headline CPI.
3. Judge rent on local conditions, using comparable listings and postcode vacancy, not national rent growth.

The next tests are the RBA's forecasts on 3 November, SQM's October vacancy in mid-November and the October monthly CPI in late November.