Weighing the risk of a bank’s clients is not the same as weighing the risks of the bank.

If bank regulators are concerned, like for instance now with uncleared derivatives, it is one thing for them to order the bank to increase the capital it holds against all not risk weighted assets, let us say from 6 to 6.2 percent, and quite another, to target specific assets with a higher capital requirements. The first adjusts the capital to the overall risk level of that banks activity, the second just distorts and discriminates against what the regulator perceives is risky. 

“An nescis, mi fili, quantilla prudentia mundus regatur?” Axel Oxenstierna, 1583 – 1654