The Federal Reserve is pondering the potential of another round of MBS purchases if Fed officials collectively decide that more bond buying is required to spur growth, but industry observers say that the central bank’s repeat of such a course of action will have a marginally helpful effect at best. The Fed has been sending out signals that it is considering taking further action to encourage the sputtering recovery, including Chairman Ben Bernanke’s testimony before both chambers of Congress this week in which he said the central bank is “prepared to take further action as appropriate,” although he wouldn’t commit to a specific action. “There are a range of possibilities. A logical range includes...