The big concern is what happens after QE, with a common opinion being that when Bernanke the puppet master removes his hand then the puppet will sag. When Quantitative Easing purchased Treasuries and MBS, the prices of substitute securities certainly increased. But because most institutions and people that own investment bonds don't think of them as substitutes for consumption, it did little to inflate the price of consumer goods. Perhaps QE would have gotten deeper into the economy if the Fed had purchased assets that most households own, like used cars and used appliances. But I digress.
Just because the Fed stops buying securities doesn't mean that the money that they created to buy those securities suddenly disappears. That money is still out there, and will only slowly dissipate as the bonds mature or amortize. Ending QE changes the flow, but not the stock.
But many people really want to believe the puppet master controls the economy rather than 300 million consumers. Fortunately there have been three rounds of QE, so we can see what happened to the economy between QE1 and QE2, and between QE2 and QE3, when the Fed wasn't creating money to buy securities.
What I see is that right after earlier QE's ended, the stock market fell - but not for long and not that much. And yields on lower rated bonds did increase some after QE, but not for long and not that much. And the yields on highly rated bonds and conventional mortgage interest rates continued to fall, probably reflecting that there was still too much saving and too little investing in the real economy. And the trend on money supply (i.e. bank deposits), unemployment, and the dollar (if there was a trend) were unaffected. Graphs, graphs, graphs - see below.