The first final provision of Act 12/2023, of 24 May, on housing rights, establishes a series of price control measures to regulate housing rental contracts, to which end it amends several articles of Act 29/1994, of 24 November, on Urban Leases. It specifically adds an eleventh additional provision to this Act, which determines that "The National Statistics Institute will define, before 31 December 2024, a reference index for the annual updating of housing rental contracts, which will be set as a reference limit for the purposes of Article 18 of this Act, with a view to avoiding disproportionate increases in the cost of rental contracts".

To comply with this legislation, the INE defined the Reference Index for the Updating of Housing Rentals (known by its Spanish acronym, IRAV). The IRAV is the minimum value between the year-on-year rate of change of the Consumer Price Index, the year-on-year rate of change of the underlying Consumer Price Index and the adjusted average annual rates of change of the CPI and the underlying CPI, measured as the difference between the annual growth rates of both the Consumer Price Index and the underlying Consumer Price Index for each month and a benchmark representing expected inflation in the medium term, adjusted by a dampening coefficient.