RPIX
RPIX is the UK Retail Prices Index excluding mortgage interest payments. It removes that component, rather than removing all housing costs or all effects of interest rates on the economy. It is relevant in historical policy discussion and certain statistical comparisons. Use the specified series consistently; exclusion of one component does not turn RPIX into CPI or eliminate other methodological differences.
Worked example
If a question specifies RPIX inflation of 3%, use that measure for the requested comparison. Do not deduct a separate mortgage-interest estimate again, because the published RPIX series already excludes that component.
Common mistake
Do not describe RPIX as RPI excluding all housing costs, or use its historical policy role to claim it is the current UK inflation target measure.
Where it appears in your exams
| Qualification | Exam | Relationship | Period |
|---|---|---|---|
| ACCA | BT | Supporting | September 2026–June 2027 |
| FIA | FBT | Supporting | September 2026–June 2027 |