INNER WORKINGS OF LARGE BANKS

The episode involving the London Whale illustrates how difficult it is to learn the truth about the inner working of large banks.  Big banks profit by exploiting information and conflicts found between the world of credit and the world of securities.  Indeed, the CIO's office generated big returns for JPM over the decade or so that Iksil was with the bank. 
But the London Whale episode also shows in graphic terms why the Volcker Rule prohibitions against banks trading for their own account need to be preserved and strengthened.  There is a fundamental conflict between a bank acting as a lender and trading credit derivatives.