On 28 January 2026, the Australian Bureau of Statistics released the December quarter 2025 Consumer Price Index figures.
At the same time, the CPI framework shifted. I’ve had several property managers contact me concerned that everything had changed. It hasn’t.
Let’s simplify this.
What Has Changed? Two things.
Monthly CPI is now the primary measure of headline inflation. The quarterly CPI is calculated as the average of the three relevant monthly indexes.
The quarterly CPI has also been re-referenced. The September 2025 quarter now equals 100.00. That means the index numbers look different.
But this is the key point:
The percentage movements have not been revised. The base has changed. The growth rates have not. Same mathematics as before. The index is simply expressed from a new reference base.
What This Means for Lease Rent Reviews
Nothing in your lease has changed. Your process should not change.
You must still:
- Go back to the lease
- Identify the correct CPI clause
- Confirm which series applies
- Check the specified quarters
- Calculate the annual percentage movement between those quarters
- Apply the formula exactly as written
The lease governs the calculation. Not commentary. Not assumption. Not internal shortcuts.
The presentation of the CPI has evolved. The contractual mechanism has not.
Where Agencies Create Risk
The risk does not sit in the re-referencing.
It sits in:
- Using the wrong CPI series
- Selecting the wrong quarter
- Relying on a spreadsheet without checking the lease
- Confusing index numbers with percentage movements
- Poorly documented working papers
Re-referencing does not make CPI more complicated. Poor process does.
The Bigger Issue
Commercial property is becoming more complex. Data evolves. Regulation tightens. Clients expect precision. CPI rent reviews are often treated as routine administration. They are not.
They affect landlord income, asset value, valuation assumptions, future negotiations and your credibility as an agency.
If your team cannot confidently interpret a CPI clause and calculate it properly, that is not a statistics issue. It is a capability issue.
Strengthening Capability
At the Australian Academy of Property, we focus on practical application. No theory for theory’s sake.
Our CPI rent review sessions cover:
- Interpreting clauses correctly
- Identifying the correct CPI series
- Calculating movements accurately
- Avoiding common errors
- Building defensible documentation
If your agency would like to book CPI training, submit an expression of interest via our website www.theaap.com.au
Because in commercial property, precision compounds. And so do mistakes.
(c) Wendy Thomson – The Australian Academy of Property – February 2026
