Banks have been skipping along the yellow brick road, content in a fairytale landscape awash with quantitative easing. But the sky darkened last week, as the industry's best friend threatened to become foe. The Federal Reserve has been a reliable companion since the financial crisis, but Ben Bernanke's chatter about TOTO (the new acronym for the "timing of tapering off" of stimulus) holds deep implications.

As the Fed begins working on TOTO, it may also begin anew to deal with excessive risk taking and to ensure that banks lend money to the real economy instead of hoarding cash. One idea is to turn banking giants into munchkins – smaller banks.