The Fed believes the stimulus from quantitative easing depends on the stock of Treasuries and mortgage-backed securities that it owns, not on the flow of its purchases. If that view is correct, the future tapering of Fed purchases won’t be monetary tightening, it will a slowing pace of monetary easing.
The chart shows a hypothetical trajectory for the Fed’s bond and MBS holdings. Under the stock view, that trajectory will go through three stages, paralleling those of traditional interest rate policy:
- Quantitative easing: The Fed expands its balance sheet by buying Treasuries and MBS. Current pace: $85 billion each month.
- Quantitative accommodation: The Fed maintains its balance sheet; it buys new assets to replace older ones as they mature.
- Quantitative tightening: The Fed contracts its balance sheet by allowing assets to mature without replacement or, more aggressively, by selling them.
In this view, tapering is the final stage of quantitative easing. The Fed buys assets during tapering, but at a slower tempo. Tapering is not tightening.
That view is clear, logical, and elegant. But it utterly fails to explain why financial markets went haywire last week when Ben Bernanke and company talked about tapering.
One reason is investor expectations. The Fed has been trying to stimulate the economy not only through QE, but also by telling investors to expect easing in the future. Such forward guidance can be a powerful lever for monetary policy.
Last week, investors learned that QE might end sooner than they expected. In the stock view with expectations, that is monetary tightening. As illustrated in the second chart, future Fed policy would be tighter than financial markets had previously thought.*
This view likely explains some of the market reaction to recent Fed statements. But it’s hard to reconcile the magnitude of the movements. Suppose markets expected tapering to begin in January and now think September more likely. All else equal, that four-month difference implies a $340 billion reduction in the Fed’s ultimate portfolio. That’s something, but could that alone explain the sharp market response?
My sense it that something else must be going on as well. Some candidates include:
- Perhaps the flow of Fed purchases matters, not just the stock. This view appears much more common among traders than Fed economists. If anyone has a reference for a good articulation of this view, I’d love to see it. The flow shouldn’t matter in normal times—was the Fed tightening when the flow of purchases was essentially zero for decades before the recent crisis?—but these are hardly normal times. Perhaps the flow matters when you are at the zero lower bound?
- Perhaps world financial markets expected a much longer period of QE and are highly geared to Fed policy. If I am reading it correctly, that’s the view of Vince Foster who discusses the unwinding of the carry trade (ht Tyler Cowen)
- Perhaps something else also happened. Scott Sumner discusses one possibility: turmoil in China’s financial sector spilling over into U.S. markets.