A retail price index excluding mortgage interest payments. This is contrasted with the UK's retail price index (RPI) which includes mortgage interest. In many other countries the commonly used retail price index is calculated excluding mortgage interest, so is already an RPIX. The main argument for using an RPIX is that under the UK system, if rising prices provoke a rise in interest rates to suppress demand, the impact effect is an increase in the measured rate of inflation. The main argument for including mortgage interest in the RPI is that people with mortgages do in fact have to pay it, and it absorbs a substantial proportion of personal incomes.

• importables
• import control
• import deposit
• Import Duties Act, 1932
• import duty
• imported inflation
• import levy
• import licence
• import penetration
• import propensity
• import quota
• import restriction
• imports
• import substitution
• import surcharge
• import tariff
• imputation system
• imputed charge for consumption of non-trading capital
• imputed income
• IMRO
• incentive-compatibility
• incentives
• incidence of taxation
• income
• income approach to GDP