Since the middle of 2008, these purchases have caused the Fed's balance sheet to balloon from under a trillion dollars to nearly four trillion dollars.  This represents the greatest central bank intervention in the history of the planet, and Janet Yellen says that she does not anticipate that it will end any time soon because "the recovery is still fragile".  Of course, as I showed the other day, the truth is that quantitative easing has done essentially nothing for the average person on the street.  But what QE has done is that it has sent stocks soaring to record highs.  Unfortunately, this stock market bubble is completely and totally divorced from economic reality, and when the easy money is taken away the bubble will collapse.