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Understanding the Term Structure of
Interest Rates
Money Marketeers
New York, New York
June 14, 2005
Published in the Federal Reserve Bank of St. Louis Review, September/October 2005, 87(5), pp. 589-95

A

topic much discussed in recent
months is the relationship over the
past year or so between long-term
and short-term interest rates. Some
observers have argued that the failure of long rates
to trend up as the Fed has increased its target
federal funds rate is a puzzle. Others have argued
that Fed policy is ineffective because increasing
the rising short rate is not affecting the long rate.
I’ll not say much about the policy issue, but I
do want to address the puzzle.
However, I’m going to define the puzzle somewhat narrowly. I’ll not address the current low
level of the real rate of interest on long-term bonds.
That same puzzle existed a year ago, although it
may not have been so obvious at the time. What
I’ll discuss is the issue of why the long rate has
not increased as the Fed has raised the target
federal funds rate.
I thank my colleagues at the Federal Reserve
Bank of St. Louis—especially Ed Nelson—for their
assistance and comments.

THE RECENT TERM STRUCTURE
PUZZLE
Since June 2004, the Federal Open Market
Committee (FOMC) has increased the target federal
funds rate by 25 basis points every time they have
met, including the recent meeting on May 3.
Moreover, the federal funds futures market predicted that the Committee would raise the target
funds rate by another 25 basis points at its June

meeting. On the other hand, a key long-term
interest rate, the yield on 10-year U.S. Treasury
securities, has shown little persistent tendency
to change, either up or down, over the same
period. I refer to this discrepancy in interest rate
patterns as the recent term structure puzzle.
The eight increases in the target funds rate
took it from 1 percent to 3 percent as of May 3,
2005. The 10-year Treasury bond rate, however,
has exhibited a different pattern. If we look at
monthly average data, which I’ll use throughout
unless indicated otherwise, we can see that the
rate has not had a persistent trend since mid-2002,
when the rate was about 41/2 percent (a rate that
also prevailed at the end of 2003 and again this
spring). The monthly average level of the bond
rate increased by about 90 basis points from March
to June 2004, mostly in response to evidence of
stronger economic growth and the beginning of
Fed tightening. The June 2004 level of 4.73 percent on the bond rate was the highest since June
2002 and has not been exceeded since.
Some observers like to emphasize that the
long rate has declined since the Fed first started
raising rates in June 2004, but I think the right
observation, given the variability of the rate, is
to say that the long rate has fluctuated around
roughly 41/2 percent since mid-2002. June 2004
is not the best month to begin the analysis because
the Fed’s rate increases were foreseen some
months in advance. Based on the July 2004 federal
funds futures contract, in late 2003 the market
anticipated a funds rate of 1.25 percent or above,
but then the expected rate for July fell to nearly 1
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FINANCIAL MARKETS

percent (i) as the FOMC maintained its 1 percent
target funds rate at its January and March 2004
meetings and (ii) as a consequence of somewhat
weak economic data. When the FOMC introduced
the “measured pace” language at its meeting of
May 4, 2004, the market priced-in a policy target
of 1.25 percent for the June 2004 FOMC meeting.
In any event, I’ll frame this puzzle as the failure of
long-term interest rates to increase as short-term
interest rates have risen since the late winter and
spring of 2004.
Two phenomena deserve to be distinguished:
the level of long-term rates and the change in long
rates as short rates have risen. Low long-term rates
were already in place before the recent term structure puzzle, and some major factors behind low
long-term rates do not necessarily help in explaining the term structure puzzle, which concerns
changes in rates. Most notably, Fed Governor
Ben Bernanke (2005) has convincingly argued
that the “global saving glut” has been a depressing
factor on U.S. real and nominal interest rates since
2000. Yet this factor does not solve the term structure puzzle, for two important reasons. First, as
noted, the glut has been in force throughout this
decade, whereas the term-structure puzzle refers
to the period since early 2004. Second, the glut
is a source of downward pressure on real interest
rates at all maturities since 2001, whereas the term
structure puzzle instead refers to the recent flat
trend of the long rate despite a significant increase
in the short rate.

AVERAGE HISTORICAL BEHAVIOR
That there is a puzzle is a consequence of
just how atypical the recent behavior of the term
structure is. The funds rate and bond rate do typically move in the same direction. A linear regression of the first difference of the bond rate on the
first difference of the federal funds rate provides
a simple description of the average relationship
between the bond rate and funds rate. The regressions indicate that the contemporaneous relationship between the two series is positive and
statistically significant. For the entire period from
May 1954 to March 2005, the regression coeffi2

cient is a bit below 0.2; for the period from January
1984 to March 2005, the coefficient is a bit above
0.3. Using the period from 1984, what the coefficient means is that on average a 100-basis-point
change in the funds rate has been associated
with a 32-basis-point change in the bond rate in
the same direction. Thus, over the past year, as
the funds rate rose by 200 basis points, we should
have seen an increase of the bond rate of about
65 basis points. Depending on how you eyeball
your favorite chart of the 10-year bond rate, instead
of increasing, the bond rate has been about flat,
or down somewhat, over the past year.

THE EXPECTATIONS THEORY OF
THE TERM STRUCTURE
To decide whether there really is a puzzle, or
to make sense of the puzzle, we’ll need to call on
economic theory. According to economic theory,
a key reason why the contemporaneous relationship between the funds rate and the bond rate is
far from one-for-one is that changes in the bond
rate should be closely linked not to today’s change
in the funds rate but to revisions in expectations
of the future path of the funds rate. The theory
will provide a framework for an analysis of the
recent term structure puzzle.
The essential message of the expectations
theory of the term structure is that market forces
should make longer-term interest rates a weighted
average of the short-term interest rates expected
to prevail over the life of the bond. The investor
should be indifferent between making N consecutive investments in 1-period securities and
investing in an N-period bond. Or at least enough
investors should be indifferent to force the Nperiod bond to trade in the market at the weighted
average of the next N 1-period bonds. To take a
simple example, letting time be quarters, the
expectations theory says that the 2-quarter interest
rate should be equal to the average of today’s 1quarter interest rate and the expected 1-quarter
rate next quarter. We assume that today’s expectation of next quarter’s 1-quarter rate is based
rationally on all information available today.

Understanding the Term Structure of Interest Rates

The argument applies to bond rates of any
maturity. The simple expectations theory implies
that the 10-year bond rate reflects the expected
path over the next ten years of the short-term rate.
The 10-year bond rate at the beginning of June
2004 incorporated the 1-year rate and the next
nine expected 1-year rates, the last of which was
a 1-year rate on a security that would be issued
in June 2013 and mature in June 2014.
Similarly, the 10-year rate prevailing at the
beginning of June this year incorporated the current 1-year rate and the next nine expected 1-year
rates, the last of which was a 1-year rate on a
security that would be issued in June 2014 and
mature in June 2015. After comparing the 10-year
bond from a year ago with the one today, we see
that nine of the ten 1-year periods are the same.
Today’s 10-year bond does not include the 1-year
rate prevailing in June 2004—that security has
matured. Today’s 10-year bond does include the
expected 1-year rate on a security maturing in
June 2015. Thus, the difference in the yields on the
two 10-year bonds—last June’s and this June’s—
reflects substitution of (i) the expected 1-year
rate for a security to be issued in June 2014 for
(ii) the 1-year rate in the market in June 2004 for
the security that has just matured in June 2005,
plus revisions in the expected 1-year rates to prevail every year from 2005 through 2013. The key
to understanding changes in the 10-year rate is
to understand revisions in those nine expected
1-year rates.
To understand the process by which expected
future 1-year rates are revised, it is useful to partition the 1-year rate into a real rate and an inflation premium. How might we anticipate far-off
expected real short rates to behave? This variable
should respond to new information about the real
shocks likely to be facing the economy several
years in the future. It would be tempting to think
that such new information arises so infrequently
that the distant short-term real rate could be
treated as constant.
There is considerable evidence against this
presumption, however. For example, Laubach
(2003) finds that expectations of short-term nominal interest rates beyond five years in the future

fluctuate in response to the changes in multiyear
budget deficit projections, and some of this fluctuation may reflect revisions to expected real rates.
It is not hard to imagine other information that
might rationally affect investor expectations about
distant real rates. Ultimately, the issue is an empirical one and it does appear that the expected real
short rate fluctuates considerably in practice.
Historically, expected future nominal short
rates have often fluctuated in response to changes
in inflation expectations. Over the past year,
distant inflation expectations, as measured by
the spread between conventional and inflationprotected bonds, have not changed markedly.
Thus, we can proceed by assuming that long-term
expectations of inflation have remained roughly
constant in the past year because of confidence
in Federal Reserve policies and, in the absence
of information to the contrary, that there is no new
information about far-off real rates. With these
assumptions, the change in the long rate is driven
by new information about the medium-term path
of short-term real interest rates.
For example, if newly published data suggest
greater pressure on aggregate demand in the years
immediately ahead, agents will expect a greater
degree of offsetting pressure from the Federal
Reserve in the form of higher real interest rates,
and the expectation of future real rates will be
higher than the expectation based on the prior
period’s information set. My emphasis in this
discussion is that new information about the state
of the economy drives changes in long-term
interest rates.

A DETAILED LOOK AT
JANUARY 2004–MAY 2005
Consider the behavior of bond rates since
the beginning of 2004 from the perspective of
the expectations theory of the term structure. In
January 2004, the 10-year bond rate was 4.15
percent; in January 2005, it was 4.22 percent. I’ll
concentrate on information that has created revisions to future expected short rates.
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FINANCIAL MARKETS

Table 1
Selected Changes in the 10-Year Treasury Bond Rate, January 2004–May 2005
Date

Bond-yield change,
basis points

Main news item

Source

–12

Weaker-than-expected growth in services sector

Reuters

1/9/2004

–16

Weaker-than-expected payroll data

1/28/2004

+11

Federal Reserve drops “for a considerable period”
language from FOMC statement

NYT

3/5/2004

–19

Weaker-than-expected payroll data

WSJ

4/2/2004

+24

Higher payroll data

WSJ

4/13/2004

+10

Weaker-than-expected retail sales for March 2004

5/7/2004

+16

Better-than-expected payroll data

6/15/2004

–20

Better-than-expected May inflation; reaction to
Greenspan Senate testimony

7/16/2004

–12

Better-than-expected June inflation

DJNW

7/27/2004

+13

Better-than-expected July consumer confidence

DJNW

8/6/2004

–19

Lower-than-expected payroll data

10/8/2004

–11

Weaker-than-expected payroll data

DJNW

10/27/2004

+10

Higher oil prices

DJNW

11/5/2004

+11

Better-than-expected payroll data

12/3/2004

–13

Weaker-than-expected payroll data

DJNW

12/16/2004

+10

Continuing reaction to FOMC statement

DJNW

3/9/2005

+14

Concern about spike in oil prices

4/15/2005

–10

Continued rise in energy prices. Disappointing reports
from Ford and GM

Bloomberg

4/21/2005

+10

Better-than-expected manufacturing report and jobless
claims data

Bloomberg

1/6/2004

DJNW

DJNW
WSJ
FT

WSJ

WSJ

NYT

NOTE: DJNW, Dow Jones News Wire; FT, Financial Times; NYT, New York Times; WSJ, Wall Street Journal. Dates refer to the date of
the interest rate change; sources refer to same-day wire reports and next-day newspaper reports on the principal economic news
accompanying the bond rate movement.

Consider revisions to expected real short rates
in immediately coming years. In past tightenings,
such as in 1994, policy-induced increases in real
rates led to sharp contemporaneous increases in
bond rates. The past year has not repeated this
phenomenon because the Federal Reserve indicated its tightening intentions well in advance
and because the economy has performed about
as expected.
An indication of what markets were expecting as of January 2004 is given by the Blue Chip
Consensus forecast for real gross domestic product
4

(GDP) growth in 2004 of 4.6 percent. In the event,
U.S. real GDP growth in 2004 was 4.4 percent. In
2004, the economy performed as close to expected
as we will find in the historical record. Events
have not much changed the outlook for 2005
either. In January 2004, the Blue Chip Consensus
forecast for 2005 real growth was 3.7 percent; the
latest (June 10, 2005) Blue Chip forecast is for real
growth of 3.5 percent, an extremely small downward revision from the expectation prevailing in
January 2004.

Understanding the Term Structure of Interest Rates

To study this matter more carefully, I’ve
examined large daily movements of the 10-year
bond rate since January 2004. These are listed in
Table 1. The criterion for determining a “large”
movement is a change of 10 basis points or more
in the bond rate.
See the table for details; I will provide here
the flavor of major financial news that occurred
on some of the “large change” days. The sluggish
recovery of employment during this expansion
was reflected in weak payroll data that surprised
the market on January 9, 2004, and March 5, 2004,
leading to declines in the bond rate of 16 basis
points and 19 basis points, respectively. These
employment reports led to revisions of market
expectations toward a slower expected withdrawal
by the Fed of its accommodative policy stance,
and, accordingly, expectations of real short rates
over the next few years declined.
As another example, the oil price spike on
March 9, 2005, was associated with an increase
in the bond rate of 14 basis points. Such bond
rate increases can be interpreted two ways. One
interpretation is that markets did not revise
upward their expectations of future inflation but
did revise upward their expectations of the Fed
monetary policy required to keep inflation stable.
Alternatively, the bond rate increase may have
reflected expectations that the Fed would accommodate a temporary increase in inflation in the
wake of the oil shock.
Expectations of future monetary policy have
affected the bond rate significantly from time to
time. A recent study by Gürkaynak, Sack, and
Swanson (2005), covering a period earlier than
that considered here, finds that news about likely
future FOMC actions on the funds rate has an
important effect on the bond rate, distinct from
FOMC actions on the current funds rate. This
finding is, of course, in line with the expectations
theory. In the period considered here, news about
future policy increased bond rates by 11 basis
points on January 28, 2004, when the FOMC
1

Radcliffe Committee (1959, paragraph 447).

2

Burns (1977, p. 724).

dropped from its press release the phrase that it
expected policy accommodation to prevail “for
a considerable period.” Once this phrase was
dropped, markets revised their expectations of
short rates to a higher path than previously, and
bond rates accordingly were immediately revised
upward.
Although certain data releases did surprise
the market, over the period as a whole the data
came in about as expected, contributing to the
absence of a trend in the bond rate over the period
at issue. Likely policy responses to economic data
were also known in advance; and, in the absence
of economic surprises, FOMC decisions on the
funds rate were much as expected. Thus, there
was no particular reason over this period for the
market to revise its expectations of future interest
rates continuously in one direction; the bond rate
fluctuated in response to arriving information,
but ended up about where it started.
The argument I am making is not a new one.
There is a huge literature on the expectations
theory of the term structure of interest rates, and
policymakers have long been aware of the basic
ideas. For example, the Radcliffe Committee, a
U.K. inquiry into monetary policy in the late
1950s, noted that “It is generally agreed that the
more temporary a rise in short rates is expected
to be, the less it will cause long rates to rise;
correspondingly, the more temporary a drop is
expected to be, the less will long rates fall.”1
Arthur Burns, then Federal Reserve Chairman,
observed in 1977 that “Long-term interest rates,
of course, are of much larger significance to the
economy than short-term rates; but the long-term
rates are also especially sensitive to inflationary
expectations.”2 In a 1976 paper, I studied the
implications for monetary policy of the expectations theory and concluded that the “implications
of the rational expectations hypothesis for macro
modeling are profound... This point is of greatest
importance for the auction markets in financial
assets” because the expectations theory tells us

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FINANCIAL MARKETS

that “long-term interest rates adjust immediately
and fully in response to new information.”3
The expectations theory of the term structure
has been severely criticized on a number of
grounds, but for the problem at hand I believe
that the theory tells the basic story correctly. In
sum, economic surprises have been minimal over
the past year and there has been no reason for
significant revision in expected future short-term
interest rates. Thus, there has been no reason for
a significant trend in long-term interest rates.

FULL CIRCLE
I began by discussing the average term structure relationship, in which long rates change by
about 30 basis points for every 100-basis-point
change in short rates. Now I’ll circle back to that
topic.
The average relationship reflects average
business cycle experience in which information
surprises change expectations about future short
rates. But a casual glance at the data will show
how variable these periods have been. In some
cases, long rates rose by much more than 30 basis
points for every 100-basis-point increase in short
rates, and in some cases much less. For example,
over the 12 months ending July 1987, the bond
rate rose by 115 basis points while the federal
funds rate was rising by only 2 basis points. In
contrast, over the 24 months ending in July 1963,
the 10-year bond rate rose by only 10 basis points
while the federal funds rate was rising by 185
basis points. Clearly, I’ve picked out particular
cases to serve as examples; but I can assure you
that, if you look at the data systematically, you
will find that the average term structure relationship of about 30 basis points on the bond rate for
every 100 basis points on the funds rate is the
average of very diverse experience. If I were writing a Ph.D. thesis, I could explore in great detail
the flow of information and how both short and
long rates responded as new information changed
3

6

Poole (1976, pp. 471, 503).

expectations about inflation, real growth, and
Fed policy.
Because the role of changes in inflation
expectations has been so important historically,
but not very important over the past decade or
so, consider an example from the 1980s. The 10year bond rate declined sharply over 1984-86,
from 11.67 percent in January 1984 to 7.11 percent
in December 1986. Kozicki and Tinsley (2005,
p. 427) suggest that this decline reflected continued
adjustment of 10-year-ahead expectations of inflation in the wake of the Volcker disinflation. They
argue that the decline in consumer price index
(CPI) inflation to about 4 percent in 1983 was not
accepted as a lasting change until the mid-1980s,
whereupon it became more fully reflected in
long-term bond yields.
An episode that more closely resembles the
2004 experience is the period 1987-89. Here the
FOMC raised the target federal funds rate sharply,
but the long rate was fairly trendless. Kozicki and
Tinsley (2005, Figure 1) show that the late 1980s
was a period where 10-year-ahead expectations
of inflation continued to decline, even though
1-year-ahead expectations rose. The rise in 1-yearahead expectations probably reflected inflation
already in the pipeline. Actual Fed policy over
this period was, by contrast, disinflationary. It
seems that this episode corresponds to one where
the Fed adjusted down its long-run inflation objective. The long-term bond market understood this
change and discounted the rise in CPI inflation
as not reflecting the long-term direction of monetary policy.

FINAL THOUGHTS
It should be clear by now that I do not believe
that there is a term structure puzzle reflected in
interest rate behavior over the past year or so.
Recent experience is unusual but far from unprecedented. The real economy has performed very
close to expectation at the beginning of 2004. The
major surprise has been the large increase in

Understanding the Term Structure of Interest Rates

energy prices. The market has interpreted this
increase as a relative price change and not a sign
of higher long-run inflation. The spread between
conventional and inflation-protected bonds has
increased over the near-term horizon but not over
the period 5 to 10 years out.
The fact that the 10-year bond has not exhibited a persistent trend over the past 18 months or
so while the Fed has been increasing the target
federal funds rate by 200 basis points is not evidence that something is awry with monetary
policy. Think of the issue this way. At the beginning of a planning period the Fed has in mind a
probable course for the economy and expectations
about the policy adjustments that will be consistent with long-run policy objectives. Suppose the
market has the same understanding as the Fed.
Suppose also that events turn out largely as
expected. Then, everything goes according to plan,
including policy adjustments and the course of
bond rates. In fact, in January 2004 the eurodollar
futures contract for June 2005 traded at an average
rate of 2.81 percent, which was not far off the
target federal funds rate of 3.0 percent set by the
FOMC on May 3, 2004.
I am not claiming that the Fed had a firm plan
in mind in January 2004 to reach a target federal
funds rate of 3 percent in May 2005, but rather
that events have simply worked out that way,
corresponding rather closely to the market’s best
guess as to how events would unfold. In any event,
the fact that everything goes about as expected is
certainly not evidence of a policy problem.
I would be delighted, as would professional
forecasters, for the string of accurate forecasts to
continue. But we would be well advised not to
forget those forecast standard errors. They have
not vanished. With respect to forecast errors, the
future is more likely to be like the past several
decades than like the past year. If real growth
and/or inflation depart significantly from current
expectations, then we will see a persistent trend

in the bond rate. I hope we do not see such an
outcome, for I believe that the current outlook
for the economy is quite favorable. I hope that
current expectations are realized.

REFERENCES
Bernanke, Ben S. “The Global Saving Glut and the
U.S. Current Account Deficit.” Homer Jones Lecture,
Federal Reserve Bank of St. Louis, St. Louis,
Missouri, April 14, 2005;
http://www.federalreserve.gov/boarddocs/
speeches/2005/20050414/default.htm.
Burns, Arthur F. Statement before the Committee on
Banking, Finance and Urban Affairs, U.S. House of
Representatives. Federal Reserve Bulletin, August
1977, 63, pp. 721-28.
Gürkaynak, Refet S.; Sack, Brian and Swanson, Eric.
“Do Actions Speak Louder Than Words? The
Response of Asset Prices to Monetary Policy Actions
and Statements.” International Journal of Central
Banking, May 2005, 1(1), pp. 55-93.
Kozicki, Sharon and Tinsley, P.A. “What Do You
Expect? Imperfect Policy Credibility and Tests of
the Expectations Hypothesis.” Journal of Monetary
Economics, March 2005, 52(2), pp. 421-47.
Laubach, Thomas. “New Evidence on the Interest
Rate Effects of Budget Deficits and Debt.” Finance
and Economics Discussion Series Paper No. 2003-12,
Federal Reserve Board, April 2003.
Poole, William. “Rational Expectations in the Macro
Model.” Brookings Papers on Economic Activity,
April 1976, 2(76), pp. 463-505.
Radcliffe Committee. Report: Committee on the
Working of the Monetary System. London: Her
Majesty’s Stationery Office. Command Paper No. 827,
August 1959.

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