By Sid Ruttala 

Large cap investing through a rate hiking cycle is rarely about the decision itself. By the time a central bank moves, the market has usually priced most of it. The harder and more useful work is reading what comes next, and understanding which parts of a portfolio are genuinely exposed and which are simply caught in the noise. 

This week delivered both halves of that puzzle within 24 hours. On Tuesday, the RBA rate hike everyone expected arrived, taking the cash rate to its highest level in 15 years. On Wednesday, the inflation numbers landed, and the headline figure jumped to 4.0%. 

On the surface, that looks like a central bank chasing an inflation problem that is getting worse. Look one layer down and the picture is more balanced. Underlying inflation has not moved for three months, and the jump in the headline rate was driven largely by fuel. 

For ASX investors, the distinction matters. It shapes whether the Reserve Bank is close to the end of this cycle, and which large cap sectors are most exposed if it is not. 

The RBA rate hike: four hikes, one message 

On 29 September the Reserve Bank’s Monetary Policy Board lifted the cash rate by 25 basis points to 4.60%. It was the fourth increase of 2026, following moves in February, March and May, and it takes rates to their highest level since late 2011. The decision was unanimous. 

The move was well flagged. Markets were pricing roughly a 92% chance of a hike in the lead up, up from around 44% a month earlier, after a run of hawkish commentary from Governor Michele Bullock and senior RBA officials. The Governor’s remark that higher unemployment would be needed to bring inflation under control did a lot of the work. 

The Board’s statement was firm. It said inflation is still too high, that a further tightening in financial conditions is warranted, and that it will raise the cash rate again if needed. It also acknowledged that the earlier hikes had tightened financial conditions and that the economy appeared to be slowing. 

That last point is easy to skim past. It is a central bank telling you its medicine is working, while reserving the right to administer another dose. 

For households, the effect is concrete. On an average mortgage of around A$731,000, this hike alone adds roughly A$110 a month in repayments, on top of three earlier increases this year. 

What the inflation numbers actually said 

The Australian Bureau of Statistics released the August CPI on 30 September. The key figures were these. 

Headline CPI rose 4.0% in the 12 months to August, up from 3.5% in July. That was slightly below the 4.1% economists had expected. In the month itself, prices rose 0.4%, again a little under forecast. 

Trimmed mean inflation, the RBA’s preferred measure of underlying price pressure, was 3.6%. That is unchanged from July, and it has held at that level for three consecutive months. 

The headline jump had clear causes. Automotive fuel prices rose 14.8% in August alone, reflecting higher global oil prices and the expiry of the federal fuel excise relief that ran from April through August. New dwelling prices rose 5.4% over the year as builders passed on higher materials and labour costs. 

Why the core matters more than the headline 

The expiry of a temporary excise cut is a one off step in prices. It lifts the annual rate for 12 months and then drops out of the calculation. Central banks generally look through effects like this, provided they do not feed into wages and broader price setting. 

The trimmed mean is designed to strip out exactly these kinds of large, idiosyncratic moves. A reading that has sat at 3.6% for three months suggests underlying inflation is sticky, but not accelerating on a 12 month view. 

Markets took that message. Expectations of a further hike in November eased, and the Australian dollar fell after the release. That reaction makes sense. A central bank that has just raised rates, sees the economy slowing and watches core inflation stall has a reasonable case to pause and assess. 

But the core number deserves a caveat, and investors should not skip it. 

The uncomfortable number 

EY senior economist Paula Gadsby pointed out that, on a six month annualised basis, trimmed mean inflation was running at 3.9% in August. That is above the 12 month figure of 3.6%. 

In plain terms, the most recent six months have been hotter than the six months before them. The 12 month average is flattering the trend. If that momentum continues, the RBA’s patience may be shorter than the market now assumes. 

The calendar adds to the tension. The September CPI is due on 28 October, and the next RBA decision is on 3 November. One more firm monthly print could put a November hike straight back on the table. 

This is why it pays to be measured about calling the peak. The data says “possibly close”. It does not yet say “done”. 

Not every large cap feels rates the same way 

The ASX 200 reached a record of 9,296 points on 6 August and has spent much of September lower, falling to its weakest level since early July in mid September as rate expectations firmed. But the broad index hides very different sensitivities. 

Banks are the most debated group. Higher rates can support net interest margins, particularly through returns on deposits and capital. But they also slow credit growth and, with a lag, lift arrears and bad debts. The RBA is openly seeking a softer labour market, and rising unemployment is the main driver of bank credit losses. Valuation sharpens the issue. Commonwealth Bank of Australia (CBA) has traded on a premium multiple for some time. A hike will not break a well capitalised bank, but it does test a share price that already assumes a great deal is going right. 

Real estate investment trusts and long duration assets feel rates through two channels: higher funding costs and a higher discount rate applied to cash flows that arrive many years from now. Goodman Group (GMG), an industrial property and data centre developer, has been a visible example, with its shares falling roughly 10% over the calendar year to the end of August. Long term structural demand does not protect a valuation from a rising discount rate. 

Consumer discretionary companies sit downstream of the mortgage belt. Four hikes in a year meaningfully reduce disposable income for indebted households, and small businesses are reporting softer sales. 

Resources and healthcare are less directly exposed to domestic rates. Their earnings are driven far more by global commodity prices, currency and product cycles. They are not immune to a global slowdown, but they are not where the local rate risk is concentrated. 

The practical point is that “the market” does not have a single interest rate exposure. Portfolios do, and they can differ a great deal depending on sector weights. 

Peak cash rate is not the same as peak bond yields 

There is a common playbook for the end of a hiking cycle. Investors wait for the central bank to signal a peak, then buy rate sensitive sectors such as property trusts, infrastructure and long duration growth names in anticipation of falling yields. 

That playbook has worked in past cycles. The risk this time is that it assumes long term bond yields will follow the cash rate down. 

The RBA controls the overnight rate. It does not control the global price of long term money, which is being pushed higher by large government deficits, the capital demands of the AI build out and the cost of energy security. As Darren Katz explores in this week’s companion piece, US 10 year Treasury yields reached around 5% in September, their highest since 2007. Australian two year government bond yields were already sitting at around 5.06% after the decision, above the cash rate. 

If the RBA pauses but global long rates stay elevated, the valuation relief that rate sensitive sectors usually enjoy at the peak may be more muted than history suggests. Pausing is not the same as cutting, and cutting is not the same as cheap money. 

Risks to this view 

Several outcomes would change the analysis. 

Inflation could prove stickier than the 12 month trimmed mean implies, as the six month annualised figure warns. A hike in November or beyond would weigh again on banks, property and consumer names. 

Oil remains a wildcard. The conflict in the Middle East has already lifted fuel prices sharply, and a further escalation would feed back into headline inflation and expectations. 

Conversely, the economy could slow faster than expected. A sharper rise in unemployment would bring rate cuts forward, which would help rate sensitive sectors but hurt bank earnings through higher credit losses. 

Finally, sector rotations around policy turning points are notoriously hard to time. Investors who reposition aggressively ahead of a peak that does not arrive can pay for it. 

What long term investors should consider 

For long term investors, the practical question is not whether the RBA moves in November. It is whether the portfolio is built for a period in which rates stay high for longer than is comfortable. 

That points to a few sensible disciplines. Understand where interest rate sensitivity actually sits across holdings, rather than treating the market as one block. Favour companies with conservative balance sheets and long dated debt maturities. Be cautious about paying premium multiples for businesses whose earnings are vulnerable to a softer labour market. And treat a central bank pause as information, not as a signal to rush back into everything rate sensitive. 

Large cap investing in this environment is less about predicting the next decision and more about owning businesses that can keep compounding whatever the next decision turns out to be. 

TAMIM Takeaway 

The RBA lifted the cash rate to 4.60% this week, its fourth hike of 2026, and headline inflation jumped to 4.0% on the back of fuel prices. Underlying inflation, however, has held at 3.6% for three months, and markets have moved to price a pause. 

What the market may be missing is the gap between a pause in the cash rate and a fall in long term borrowing costs. Global bond yields are being driven by forces the RBA cannot control, so the usual end of cycle rally in rate sensitive sectors may be less generous this time. The six month trend in core inflation is also hotter than the headline suggests. 

For long term investors, the right mindset is patient and selective. Focus on balance sheet strength, be honest about valuation, and know where rate risk sits in the portfolio. The cycle may be close to its peak, but the cost of capital may stay higher for longer than many expect. 

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Disclaimer: Commonwealth Bank of Australia (ASX: CBA) and Goodman Group (ASX: GMG) are mentioned for illustrative purposes.