His fixed rate ends in November, the same month the RBA decides. Should he wait for one inflation number?

He is 38. He bought a four-bedroom house in Brisbane's north in 2021 with his wife, fixed most of the loan at a rate that now looks like a typo, and spent the next five years paying it down and watching the valuation climb.

The fixed term ends in the second week of November. He has known the date for years. What he did not plan for was the Reserve Bank's last meeting of the year landing in the same fortnight.

When the loan rolls to variable, his repayments go up by about $1,800 a month. His broker had pre-approved him in winter to draw on his equity and buy his first rental. Then the September rate rise arrived, and the broker's tone changed.

He is a composite, drawn from the questions we have received since the September decision. The numbers are typical of them.

The question he sent us

"My fixed rate ends in November and the RBA meets the same month. CBA says they're done, but November is 'live'. Do I hold off on the investment property until I know, or am I just going to be waiting forever?"

What the CBA chief actually said

Speaking to the ABC's Alan Kohler this week, Commonwealth Bank chief executive Matt Comyn said the bank believes the September rise was the last one for now. He also said the November meeting is live, and that the RBA's next move will depend on the quarterly inflation data released at the end of October.

Both things are true at once. The bank's base case is that hiking is finished. The bank is also not willing to rule out one more.

He said the September rise was driven by global pressures, the Middle East conflict and fuel prices among them. He said CBA is seeing more customers needing financial assistance or struggling to meet repayments, and that households exposed to higher mortgages are cutting spending and savings.

On housing, he was direct. When rates last peaked in 2023, national prices fell 8.2 per cent. Current predictions, he noted, are for a drop of around 10 per cent. He expects prices to weaken over the rest of this year and recover if rates come down next year as expected, with a structural undersupply underneath. Housing, he said, is about 57 per cent of household wealth in this country.

So that is the honest picture from the person running Australia's largest mortgage book. Probably done. Possibly not. One print decides it.

The answer: the inflation number is not his problem

Here is the mistake we see every time rates are in the news. People treat the RBA decision as the thing they need to get right. They cannot control it or predict it, and the bank that wrote the loan cannot either.

What he can control is whether his position survives either outcome. That is a maths exercise, and it takes an afternoon.

Start with the $1,800. That rise is coming in November whatever the RBA does, because it is the fixed term ending, and nothing in Martin Place changes it. It has to be absorbed first.

Then add one more 0.25 percentage point rise on top. On a loan of around $680,000 that is roughly $110 a month. Put the two together and ask whether the household still has headroom. If the answer is yes with room to spare, the November meeting is background noise. If the answer is no, the November meeting is still not the issue. The fixed-rate cliff is, and it was always going to be.

Now run the rental the same way. Price it at today's variable rate plus one more rise, with a vacancy allowance and a maintenance allowance, and see whether the shortfall is something the household can carry without touching the buffer. If it can, the purchase is sound in both scenarios. If it only works in the no-rise scenario, it was never a sound purchase. It was a bet on the inflation print.

What waiting actually costs

"Wait until November" sounds free. It costs more than it looks.

If the RBA holds, he has learnt nothing he did not already know from CBA's own base case, and he is shopping in December with everyone else who waited.

If the RBA lifts, he has learnt that his structure needed a $110 buffer he should have built regardless.

Either way, the decision in front of him was always the same one: does this structure hold at the higher number. Answer that and the calendar stops mattering.

What it means for you

If you have equity and are thinking about using it, the CBA interview is useful for one reason. It tells you exactly which stress test to run and when. Serviceability at the current rate plus one more rise, done before the end of October, before you sign anything and before you refinance.

Check these this month, in this order:

• Your cash-flow headroom after any fixed-rate expiry, not before it.
• Your fixed and variable split, and whether one more rise lands on all of the debt or part of it.
• Whether your deposit and buffer sit in an offset or somewhere that earns you nothing.
• Whether the rental you are pricing works at today's rate plus 0.25, or only at today's rate.

Mr Comyn said households are feeling it and more customers are asking for help. Those are the households that priced their loans at the rate on the day, with no room for the next one.

This is general information, not personal advice. Your lender, your broker or your adviser can run your actual numbers.

The Ripehouse reframe

Rates will move. They always have. Over a full cycle a well-built portfolio sees rises, cuts, a correction and a recovery, and Mr Comyn described all four in a single interview.

The investors who come through those cycles ahead did not guess the RBA correctly. They bought the right asset, on the right street, with a buffer that assumed the next decision would go against them.

Street matters more than the cash rate. Two streets in the same suburb can be having completely different outcomes right now, one with stock sitting for months and one with buyers still competing, and no RBA decision changes which is which. The headline move is national. The result is local.

He does not need to know what happens in November. He needs a structure that does not care.

Want to see how we stress-test a decision like this street by street, before the rate decision rather than after it? Join Jacob's free live webinar.