speeches · January 2, 2004
Speech
Ben S. Bernanke · Governor
For release on delivery
5:30 P.M. EST (2:30 P.M. PST)
January 3, 2004
Conducting Monetary Policy at Very
Low Short-Term Interest Rates
Ben S. Bernanke, Member
and
Vincent R Reinhart*
Director, Division of Monetary Affairs
at the
Meetings of the American Economic Association
San Diego, California
January 3, 2004
"'Board of Govemors of the Federal Reserve System, Washington, D.C. We have benefited from
the research of, and many discussions with, numerous colleagues. However, the views expressed
here are our own and not necessarily shared by anyone else in the Federal Reserve System.
Can monetary policy committees, accustomed to describing their plans and actions in terms of the level of a
short-term nominal interest rate, find effective means of conducting and communicating their policies when that rate
is zero or close to zero? The very low levels of interest rates in Japan, Switzerland, and the United States in recent
years have stimulated much interesting research on this question, and some has been applied in the field. Moreover,
their minds concentrated by the possibility of having the policy rate pinned at zero, central bankers have responded
flexibly, making changes in their operating procedures and communications strategies. Our purpose in this paper is
to give a brief progress report and overview of current thinking on the conduct of monetary policy when short-term
interest rates are very low or even zero.
Monetary policy works for the most part through financial markets. Central bank actions are designed in
the first instance to influence asset prices and yields, which in turn affect economic decisions and thus the evolution
of the economy. When the short-term policy rate is at or near zero, the conventional means of effecting monetary
ease-lowering the target for the policy rate--is no longer feasible, but monetary policy is not impotent. In this paper
we will discuss three alternative (but potentially complementary) monetary strategies for stimulating the economy
that do not involve changing the current value of the policy rate. Specifically, these alternatives involve (1)
providing assurance to fmancial investors that short rates will be lower in the future than they currently expect, (2)
changing the relative supplies of securities (such as Treasury notes and bonds) in the marketplace by shifting the
composition of the central bank's balance sheet, and (3) increasing the size of the central bank's balance sheet
beyond the level needed to set the short-term policy rate at zero ("quantitative easing"). In the final section, we
briefly discuss the macroeconomic costs and benefits of very low interest rates, an issue that bears on the question of
whether the central bank should take the policy rate all the way to zero before undertaking some of the alternatives
we describe.
I. Shaping Interest-Rate Expectations
The pricing oflong-lived assets, such as long-term bonds and equities, depends on the entire expected
future path of short-term interest rates as well as on the current short-term rate. Prices and yields oflong-lived
assets are important determinants of economic behavior because they affect incentives to spend, save, and invest.
Thus, a central bank may hope to affect financial markets and economic activity by influencing financial market
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participants' expectations of future short-tenn rates. Important recent research has examined this potential channel
of influence in fully articulated models based on optimizing behavior; see Michael Woodford (2003, chapter 6),
Lars Svensson (2001), and Gauti Eggertson and Woodford (2003). This literature suggests that, even with the
overnight nominal interest rate at zero, a central bank can impart additional stimulus by offering some fonn of
commitment to the public to keep the short rate low for a longer period than previously expected. This commitment,
if credible, should lower yields throughout the tenn structure and support other asset prices.
In principle, the central bank's policy commitment could take either of two fonns: unconditional and conditional.
An unconditional commitment is a pledge by the central bank to hold short-tenn rates at a low level for a fixed
period of calendar time. In this case, additional easing would take the fonn of lengthening the period of policy
commitment. However, given the many shocks that the economy is heir to, as well as other imponderables that
affect the outlook, a policymaking committee might understandably be reluctant to tie its hands by making an
unconditional promise, no matter how nuanced, about policy actions far into the future. An alternative strategy is to
make a conditional policy commitment, one that links the duration of promised policies not to the calendar but to the
evolution of economic conditions. For example, policy ease could be promised until the committee observes
sustained economic growth, substantial progress in trimming economic slack, or a period of inflation above a
specified floor.
In practice, central banks appear to appreciate the importance of influencing market expectations about
future policy. For example, in May 2001, with its policy rate virtually at zero, the Bank of Japan promised that it
would keep its policy rate at zero for as long as the economy experienced deflation--a conditional policy
commitment. More recently, the Bank of Japan has been more explicit about the conditions under which it would
begin to raise rates; for example, it has been specified that a change from deflation to inflation that is perceived to be
temporary will not provoke a tightening. In the United States, the August 2003 statement of the Federal Open
Market Committee that ''policy accommodation can be maintained for a considerable period" is another example of
commitment. The close association of this statement with the Committee's expressed concerns about "unwelcome
disinflation" implied that this commitment was conditioned on the assessment of the economy. The conditional
nature of the commitment was sharpened in the Committee's December statement, which explicitly linked
continuing policy accommodation to the low level of inflation and the slack in resource use. More generally, in
recent years central banks have devoted enonnous effort to improving their communications and transparency; a
major benefit of such efforts should be a greater ability to align market expectations of policy with the policymaking
committee's own intentions.
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Of course, policy commitments can influence future expectations only to the extent that they are credible.
Various devices might be employed to enhance credibility; for example, the central bank can make securities
purchases or issue financial options that make it quite costly, in financial terms, to renege on its commitments
(Clouse et aI., 2003). An objection to this strategy is that it is not entirely clear why a central bank, which has the
power to print money, should be overly concerned about its financial gains and losses. Eggertsson and Woodford
(2003) point out that a government can more credibly promise to carry out policies that raise prices when (1) the
government debt is large and not indexed to inflation and (2) the central bank values the reduction in fiscal burden
that reflationary policies will bring (for example, because it may reduce the future level of distortionary taxation).
Ultimately, however, the central bank's best strategy for building credibility is to ensure that its deeds match its
words, thereby building trust in its pronouncements. The requirement that deeds match words has the consequence
that the shaping of market expectations is not an independent instrument of policy in the long run.
II. Altering the Composition of the Central Bank's Balance Sheet
Central banks typically hold a variety of assets, and the composition of assets on the central
bank's balance sheet offers another potential lever for monetary policy. For example, the
Federal Reserve participates in all segments of the Treasury market, with most of its current
asset holdings of about $670 billion distributed among Treasury securities with maturities
ranging from four weeks to thirty years. Over the past fifty years, the average maturity of the
Federal Reserve System's holdings of Treasury debt has varied considerably within a range from
one to four years. As an important participant in the Treasury market, the Federal Reserve might
be able to influence term premiums, and thus overall yields, by shifting the composition of its
holdings, say from shorter-to longer-dated securities. In simple terms, if the liquidity or risk
characteristics of securities differ, so that investors do not treat all securities as perfect
substitutes, then changes in relative demands by a large purchaser have the potential to alter
relative security prices. (The same logic might lead the central bank to consider purchasing
assets other than Treasury securities, such as corporate bonds or stocks or foreign government
bonds. The Federal Reserve is currently authorized to purchase some foreign government bonds
but not most private-sector assets, such as corporate bonds or stocks.)
Perhaps the most extreme example of a policy keyed to the composition of the central bank's
balance sheet is an announced ceiling on some longer-term yield below the prevailing rate. This
policy entails (in principle) an unlimited commitment to purchase the targeted security at the
announced price. (To keep the overall size of its balance sheet unchanged, the central bank
would have to sell other securities in an amount equal to the purchases of the targeted security.)
Obviously, such a policy would signal strong dissatisfaction on the part of the policymaking
committee with current market expectations of future policy rates.
Whether policies based on manipulating the composition of the central bank balance sheet can be effective
is a contentious issue. The limited empirical evidence generally suggests that the degree of imperfect
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substitutability within broad asset classes, such as Treasury securities, is not great, so that changes in relative
supplies within the range of U.S. experience are unlikely to have a major impact on risk premiums or term
premiums (Reinhart and Sack, 200 I). If this view is correct, then attempts to enforce a floor on the prices of
long-dated Treasury securities (for example) could be effective only if the target prices were broadly consistent with
investor expectations of future values of the policy rate. If investors doubted that rates would be kept low, the
central bank would end up owning all or most of those securities. Moreover, even iflarge purchases of, say, a
long-dated Treasury security were able to affect the yield on that security, the policy may not have significant
economic effects if the targeted security became "disconnected" from the rest of the term structure and from private
rates, such as mortgage rates.
Yet another complication affecting this type of policy is that the central bank's actions would have to be
coordinated with the central government's finance department to ensure that changes in debt-management policies
do not offset the attempts of the central bank to affect the relative supplies of securities. According to James Tobin,
the Federal Reserve's failure to coordinate adequately with the Treasury was the undoing of "Operation Twist" in
1963 (Tobin, 1973, pp. 32-33).
Despite these objections, we should not fail to note that policies based on changing the composition of the
central bank's balance sheet have been tried in the United States. From 1942 to 1951, the Federal Reserve enforced
rate ceilings at two and sometimes three points on the Treasury yield curve. This objective was accomplished with
only moderate increases in the Federal Reserve's overall holdings of Treasury securities, relative to net debt
outstanding; moreover, there is little evidence that the targeted yields became "disconnected" from other public or
private yields. The episode is an intriguing one, but unfortunately the implications for current policy are not entirely
straightforward. We know that, by 1946, the Federal Reserve System owned almost nine-tenths of the (relatively
small) stock of Treasury bills, suggesting that at the short end, the ceiling on the bill rate was a binding constraint.
In contrast, the Federal Reserve's relative holdings oflonger-dated Treasury notes and bonds fell over the period,
although the rate ceilings at these longer maturities were not breached until inflation pressures led to the
Fed-Treasury Accord and the abandonment of the pegging policy in 1951. The conventional interpretation is that
long-run policy expectations must have been consistent with the ceilings at the more distant points on the yield
curve. Less clear is the extent to which the pegging policy itself influenced those policy expectations.
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Probably the safest conclusion about policies based on changing the composition of the central bank's
balance sheet is that they should be used only to supplement other policies, such as an attempt (for example, through
a policy commitment) to influence expectations of future short rates. This combined approach allows the central
bank to enjoy whatever benefits arise from changing the relative supplies of outstanding securities without risking
the problems that may arise if the yields desired by the central bank are inconsistent with market expectations.
III. Expanding the Size of the Central Bank's Balance Sheet
Besides changing the composition of its balance sheet, the central bank can also alter policy by changing the size of
its balance sheet; that is, by buying or selling securities to affect the overall supply of reserves and the money stock.
Of course, this strategy represents the conventional means of conducting monetary policy, as described in many
textbooks. These days, most central banks choose to calibrate the degree of policy ease or tightness by targeting the
price ofreserves--in the case of the Federal Reserve, the overnight federal funds rate. However, nothing prevents a
central bank from switching its focus from the price of reserves to the quantity or growth of reserves. When stated
in terms of quantities, it becomes apparent that even if the price of reserves (the federal funds rate) becomes pinned
at zero, the central bank can still expand the quantity of reserves. That is, reserves can be increased beyond the level
required to hold the overnight rate at zero-a policy sometimes referred to as "quantitative easing." Some evidence
exists that quantitative easing can stimulate the economy even when interest rates are near zero; see, for example,
Christina Romer's (1992) discussion of the effects of increases in the money supply during the Great Depression in
the United States.
Quantitative easing may affect the economy through several possible channels. One potential channel is
based on the premise that money is an imperfect substitute for other financial assets (in contrast to the view
discussed in the previous section that emphasizes the imperfect substitutability of various nonmoney assets). If this
premise holds, then large increases in the money supply will lead investors to seek to rebalance their portfolios,
raising prices and reducing yields on alternative, non-money assets. Lower yields on long-term assets will in turn
stimulate economic activity. The possibility that monetary policy works through portfolio substitution effects, even
in normal times, has a long intellectual history, having been espoused by both Keynesians (Tobin, 1969) and
monetarists (Brunner and Meltzer, 1973). Recently, Javier Andres, J. David Lopez-Salido, and Edward Nelson
(2003) have shown how these effects might work in a general equilibrium model with optimizing agents. The
practical importance of these effects remains an open question, however.
Quantitative easing may also work by altering expectations of the future path of policy rates. For example,
suppose that the central bank commits itself to keeping reserves at a high level, well above that needed to ensure a
zero short-term interest rate, until certain economic conditions obtain. Theoretically, this action is equivalent to a
commitment to keep interest rates at zero until the economic conditions are met, a type of policy we have already
discussed. However, the act of setting and meeting a high reserves target is more visible, and hence may be more
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credible, than a purely verbal promise about future short-tenn interest rates. Moreover, this means of committing to
a zero interest rate will also achieve any benefits of quantitative easing that may be felt through non-expectational
channels.
Lastly, quantitative easing that is sufficiently aggressive and that is perceived to be long-lived may have
expansionary fiscal effects. So long as market participants expect a positive short-tenn interest rate at some date in
the future, the existence of government debt implies a current or future tax liability for the public. In expanding its
balance sheet by open-market purchases, the central bank replaces public holdings of interest-bearing government
debt with non-interest-bearing currency or reserves. If the open-market operation is not expected to be reversed too
quickly, this exchange reduces the present and future interest costs of the government and the tax burden on the
public. (Effectively, this process replaces a direct tax, say on labor, with the inflation tax.) Auerbach and Obstfeld
(2003) have analyzed the fiscal and expectational effects of a pennanent increase in the money supply along these
lines. Note that the expectational and fiscal channels of quantitative easing, though not the portfolio substitution
channel, require the central bank to make a credible commitment to not reverse its open-market operations, at least
until certain conditions are met. Thus, this approach also poses communication challenges for monetary policy
makers.
Japan once again provides the most recent case study. In the past two years, current account balances held
by commercial banks at the Bank of Japan have increased about five-fold, and the monetary base has risen to almost
30 percent of nominal GDP. While deflation appears to have eased in Japan recently, it is difficult to know how
much of the improvement is due to monetary policy, and, of the part due to monetary policy, how much is due to the
zero-interest-rate policy and how much to quantitative easing. The experience of the United States with quantitative
policies is limited to the period 1979 to 1982, when the Federal Reserve targeted nonborrowed reserves. Of course,
nominal interest rates were not close to zero at that time. The U.S. experience does suggest, however. that the
demand for reserves may be sufficiently erratic that the effects of quantitative policies may be intrinsically hard to
calibrate.
IV. Sequencing and the "Costs" of Low Interest Rates
The fonns of monetary stimulus described above can be used once the overnight rate has already been
driven to zero or as a way of driving the overnight rate to zero. However, a central bank might choose to rely on
these alternative policies while maintaining the overnight rate somewhat above zero. For example, monetary policy
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makers might attempt to influence market expectations of future short rates as an alternative to changing the current
setting of the overnight rate. Another possibility is to try to affect term premiums, expectations of future rates, or
both, by changing the composition of securities held by the central bank. (Unlimited expansion of the total volume
of securities held by the central bank is not compatible, of course, with a positive overnight rate.) The appropriate
sequencing of policy actions depends on the perceived costs associated with very low or zero overnight interest
rates, as well as on operational considerations and estimates of the likely effects of alternative combinations of
policies on the economy.
What costs are imposed on society by very low short-term interest rates? Observers have pointed out that
rates on fmancial instruments typically priced below the overnight rate, such as liquid deposits, shares in money
market mutual funds, and collateralized borrowings in the ''repo'' market, would be squeezed toward zero as the
policy rate fell, prompting investors to seek alternatives. Short-term dislocations might result, for example, iffunds
flowed in large amounts from money market mutual funds into bank deposits. In that case, some commercial paper
issuers who have traditionally relied on money market mutual funds for financing would have to seek out new
sources, while banks would need to find productive uses for the deposit inflows and perhaps face changes in
regulatory capital requirements. In addition, liquidity in some markets might be affected; for example, the incentive
for reserve managers to trade federal funds diminishes as the overnight rate falls, probably thinning brokering in that
market.
In thinking about the costs associated with a low overnight rate, one should bear in mind the message of Milton
Friedman's classic essay on the optimal quantity of money (Friedman, 1969). Friedman argued that an overnight
interest rate of zero is optimal, because a zero opportunity cost of liquidity eliminates the socially wasteful use of
resources to economize on money balances. From this perspective, the costs of low short-term interest rates can be
seen largely as adjustment costs, arising from the unwinding of schemes designed to make holding transactions
balances less burdensome. These costs are real but are also largely transitory and have limited sectoral impact.
Moreover, to the extent that the affected institutions have economic functions other than helping clients economize
on money balances (for example, if some money market mutual funds have a comparative advantage in lending to
commercial paper issuers), there is scope for repricing that will allow these services to continue to be offered. Thus
there seems to be little reason for central banks to avoid bringing the policy rate close to zero if the economic
situation warranted.
A quite different argument for engaging in alternative monetary policies before lowering the overnight rate
all the way to zero is that the public might interpret a zero instrument rate as evidence that the central bank has "run
out of ammunition." That is, low rates risk fostering the misimpression that monetary policy is ineffective. As we
have stressed, that would indeed be a misimpression, as the central bank has means of providing monetary stimulus
other than the conventional measure oflowering the overnight nominal interest rate. However, it is also true that the
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considerable Wlcertainty that surroWlds the use of these alternative measures does make the calibration of policy
actions more difficult. Moreover, given the important role for expectations in making many of these policies work,
the cotnmWlications challenges would be considerable. Given these risks, policymakers are well advised to act
preemptively and aggressively to avoid facing the complications raised by the zero lower bOWld.
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REFERENCES
Andres, Javier; L6pez-Salido, J. David and Nelson, Edward. "Tobin's Imperfect Asset Substitution in
Optimizing General Equilibrium," presented at the JMCBlFederal Reserve Bank of Chicago James Tobin
Symposium, November 14-15, 2003.
Auerbach, Alan J. and Obstfeld, Maurice. "The Case for Open-Market Purchases in a Liquidity Trap." Working
paper, University of California, Berkeley, 2003
Bernanke, Ben. "Deflation: Making Sure 'It' Doesn't Happen Here." Remarks before the National Economists'
Club, Washington, DC, November 21,2002.
• "Some Thoughts on Monetary Policy in Japan." Address to the Japan Society of Monetary Economics,
Tokyo, May 31, 2003.
Brunner, Karl and Meltzer, Allan. "Mr. Hicks and the 'Monetarists'," Economica, February 1973, 40(157), pp.
44-59.
Clouse, James; Henderson, Dale; Orphanides, Athanasios; Small, David H. and Tinsley, P.A. "Monetary
Policy When the Nominal Short-Term Interest Rates Is Zero." Topics in Macroeconomics, 2003,3(1),
article 12, pp. n.a. http://www.bepress.comibejmJtopicsJvo113/issllartI2
Eggertsson, Gaud and Woodford, MichaeL "The Zero Bound on Interest Rates and Optimal Monetary Policy."
Brookings Papers on Economic Activity, 2003, (1), pp. 139-233.
Friedman, Milton. The Optimum Quantity ofM oney and Other Essays. Chicago: Aldine, 1969.
Reinhart, Vincent and Sack, Brian. "The Economic Consequences of Disappearing Government Debt."
Brookings Paper on Economic Activity, 2000, (2), pp. 163-209.
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Romer, Christina. "What Ended the Great Depression?" Journal ofE conomic History, December 1992,52(4), pp.
757-84.
Svensson, Lars E. O. "The Zero Bound in an Open Economy: A Foolproof Way of Escaping from a Liquidity
Trap." Monetary and Economic Studies, Special Edition, February 2001,19, pp. 277-312.
Tobin, James. "A General Equilibrium Approach to Monetary Theory." Journal ofM oney, Credit, and Banking,
February 1969, 1(1), pp. 15-29 .
• The New Economics One Decade Older. Princeton, NJ: Princeton University Press, 1974.
Woodford, Michael. Interest Rates and Prices: Foundations ofa Theory ofM onetary Policy. Princeton, NJ:
Princeton University Press, 2003.
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Cite this document
APA
Ben S. Bernanke (2004, January 2). Speech. Speeches, Federal Reserve. https://whenthefedspeaks.com/doc/speech_20040103_bernanke_2
BibTeX
@misc{wtfs_speech_20040103_bernanke_2,
author = {Ben S. Bernanke},
title = {Speech},
year = {2004},
month = {Jan},
howpublished = {Speeches, Federal Reserve},
url = {https://whenthefedspeaks.com/doc/speech_20040103_bernanke_2},
note = {Retrieved via When the Fed Speaks corpus}
}