The profits being reported so far this year by the major financial firms appear to be driven by proprietary trading (trading for their own account, as opposed to those of their customers). The recent $3.44 billion profit of Goldman Sachs in the second quarter is a dramatic case in point.
Proprietary trading is a high-risk activity and signals the financial sector is returning to its bad old ways. Returns cannot be systematically high unless risk is correspondingly high.
None of this would matter if it were just private capital at stake. But Goldman, along with other major financial firms, is being guaranteed under the dubious doctrine that it is too-big-to-fail. Better there were no government guarantees. As long as these guarantees are in place, however, high-risk activity must be curtailed.
The simplest solution is that a firm should not be permitted to take insured deposits and operate what amounts to a hedge fund within the institution. Goldman is a difficult case because it is not currently relying on deposits (even though it has a bank charter). It should be told to return to a private partnership.
A firm too big-to-fail is too-big-to-exist (as a federally insured entity).