Models are complex things, but they have recently become the subject of a simple argument. Under pressure from the Federal Reserve Board, US banks are asking model vendors to open up their black boxes – and the vendors, to a greater or lesser extent, are refusing. It's a dispute that, until now, has played out in private, but banks are becoming increasingly frustrated.
The Fed crackdown came as part of this year's annual stress test, banks say. Even institutions that passed the test in March wer