I can only say: I'm sorry, America. As a former Federal Reserve official, I was responsible for executing the centerpiece program of the Fed's first plunge into the bond-buying experiment known as quantitative easing. The central bank continues to spin QE as a tool for helping Main Street. But I've come to recognize the program for what it really is: the greatest backdoor Wall Street bailout of all time. Where are we today? The Fed keeps buying roughly $85 billion in bonds a month, chronically delaying so much as a minor QE taper. Over five years, its bond purchases have come to more than $4 trillion. Amazingly, in a supposedly free-market nation, QE has become the largest financial-markets intervention by any government in world history. And the impact? Even by the Fed's sunniest calculations, aggressive QE over five years has generated only a few percentage points of U.S. growth. By contrast, experts outside the Fed, such as Mohammed El Erian at the Pimco investment firm, suggest that the Fed may have created and spent over $4 trillion for a total return of as little as 0.25% of GDP (i.e., a mere $40 billion bump in U.S. economic output). Both of those estimates indicate that QE isn't really working. Unless you're Wall Street. Having racked up hundreds of billions of dollars in opaque Fed subsidies, U.S. banks have seen their collective stock price triple since March 2009. The biggest ones have only become more of a cartel: 0.2% of them now control more than 70% of the U.S. bank assets. As for the rest of America, good luck.