Nasdaq CEO Greifeld scrutinizes proposed curb on proprietary trading

Nasdaq OMX CEO Bob Greifeld said it will be difficult to distinguish when banks are trading on their own behalf or on behalf of clients, raising questions about the viability of the White House's proposal to ban proprietary trading at major banks. An analyst recently asked whether Nasdaq knows how much proprietary trading is conducted through the exchange. "It's kind of impossible for us to answer, delineated between 'prop' and 'nonprop'. This shows the difficulty legislators will have proscribing prop trading," Greifeld said. "Once you get into what is risk [positions] versus principal [positions], it gets impossible, so I think they'd have to find a different path to go."