The Doomsday Scenario for the stock and housing bubbles is simple: the Fed's magic fails. When dropping interest rates to zero and flooding the financial sector with loose money fail to ignite the economy and reflate the deflating bubbles, punters will realize the Fed's magic only worked the first three times: three bubbles and the game is over.

So what happens when punters realize there won't be a fourth bubble? They sell. Bids disappear because who's dumb enough to bet (with Japan and Europe as lessons) that more liquidity and negative interest rates will magically work when zero interest rates didn't move the needle?

Who's foolish enough to catch the falling knife (i.e. buying plummeting assets on the way down) on the unsupported assumption that the next dose of Fed magic will reverse a bidless market?

And should the Fed start buying stocks, mortgages, housing and bonds to prop up those bidless markets, what's the message it will be sending? Desperation.If the only buyer is the money-printing central bank, that's pretty good evidence that your economy and markets are in free-fall.