Recall that when the FED was conducting POMO during QE2, they purchased fresh UST's from PD's, who took the cash and bought stocks.
Now, during QEn, the FED is buying MBS reserves from banks, who need to keep the fresh cash as reserves, since the MBS crap was marked to fantasy and would never be able to be liquidated on the open market, if a bank needed to honor their deposits.
In other words, now that everyone finally believes in QE, they ain't getting the one they think is coming......