The IRPH was marketed by banks as a less volatile index than the Euribor and as a cheaper one. The theory was that this index would not go up as much as the Euribor. However, since 2008, interest rates have crashed worldwide and the Euribor has actually been in negative territory since February 2016.
The IRPH, on the other hand, has been very slow to go down and is now considerably more expensive than the Euribor. Estimates calculate that the IRPH rate is between 1.5 and 3% higher than the Euribor. Homeowners with an IRPH-linked mortgage have therefore been paying a far higher rate than those with a loan indexed by the Euribor.
The IRPH has been widely criticised as being favourable to banks rather than the consumer. Consumer watchdogs also claim that it was imposed on clients without their knowledge or acceptance.