(34)The finalised Basel III framework no longer requires an institution that adopted the IRB Approach for one exposure class to adopt that approach for all of its non-trading book exposures. To ensure a level playing field between institutions currently treating some exposures under the IRB Approach and those that do not, a transitional arrangement should allow institutions to revert to less sophisticated approaches under a simplified procedure. That procedure should allow competent authorities to oppose requests to revert to a less sophisticated approach that are made with a view to engaging in regulatory arbitrage. For the purposes of that procedure, the sole fact that the reversal to a less sophisticated approach results in a reduction of own funds requirements determined for the respective exposures should not be considered sufficient to oppose a request on grounds of regulatory arbitrage.