The bond market’s adverse reaction after the Fed announced no new asset purchase facilities or bond buyback programs highlights the fundamental difference between interest rates and quantitative easing (QE).
Rate cuts provide ongoing support for an indefinite period until the Federal Open Market Committee chooses to reverse them. In contrast, QE programs provide a one-off, time-limited boost that has to be continually reapplied to have the same effect.
With interest rates a decision to leave rates alone represents “no change” in policy; with QE, a decision to leave the scale and duration of the buyback program unchanged is a “tightening”.
QE is time-limited because it drives up bond prices and cuts yields only as long as buybacks continue, or are expected to do so. Once planned buybacks have been completed, or are not expected to be extended, the market will revert to its natural clearing equilibrium. Repeated doses of QE are needed just to keep yields unchanged.