Item 31.12 from FRTB's documentation states the following regarding risk factor eligibility for the expected shortfall model:
A bank must determine which risk factors within its trading desks that have received approval to use the internal models approach as set out in [MAR32] are eligible to be included in the bank’s internal expected shortfall (ES) model for regulatory capital requirements as set out in [MAR33].
From this paragraph, I understand that it is only after getting a desk approved for the use of IMA that the risk factors can be deemed eligible for the expected shortfall model.
How is it possible given that the internal model needs to be up and running so to pass the P&L attribution test and backtesting, which are both necessary in order to be approved?
I think I'm a bit confused regarding the steps involved in that process.