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FEDERAL RESERVE BANK OF NEW YORK

I N E C O N O M I C S

A N D F I N A N C E

March 1999

Volume 5 Number 4

Mortgage Refinancing and the Concentration
of Mortgage Coupons
Paul Bennett, Frank Keane, and Patricia C. Mosser

Because of the concentrated distribution of interest rates on outstanding mortgages, modest
interest rate declines in 1997 and 1998 made refinancing a smart choice for a record number
of homeowners. In addition, the strong economy and the age of mortgage loans likely
contributed to the surge in refinancing activity.
In 1998, interest rates on mortgages dropped to their
lowest levels in nearly five years, prompting a record
amount of refinancing activity. Refinancings typically
rise following a drop in rates as homeowners seek to
capture interest savings. The 1998 surge, however, was
strikingly large relative to the size of the interest rate
declines that triggered it. From mid-1997 to early 1998,
thirty-year mortgage rates fell about 1 percentage point,
from just over 8 percent to just over 7 percent. During
the same period, refinancing applications increased
nearly sevenfold. When rates fell modestly again in the
second half of 1998, refinancing soared to even higher
levels. Indeed, the increases in refinancing activity
were so extraordinary that they caught even some
experienced mortgage market participants by surprise.1
This edition of Current Issues in Economics and
Finance examines why refinancings responded so
dramatically to lower interest rates in 1998. We show
that at the end of 1997, a particularly large proportion
of outstanding mortgage loans had interest rates
slightly above the rates available on new mortgages.
When interest rates fell, the gap between the rates on
existing and new mortgages widened sufficiently to
make the refinancing of these outstanding loans economically advantageous. As a result, an unusually large
number of homeowners chose to refinance in 1998.
The high concentration of loans that became cost
effective to refinance, however, cannot account for all

of the surge in refinancing activity. Favorable economic
conditions also appear to have encouraged many homeowners to refinance. In addition, the high proportion of
“moderately seasoned” mortgages in 1998—that is,
mortgages that are between two and five years old—
may have contributed to the increase in refinancing
activity.
Broad Effects of Mortgage Refinancing
Mortgage refinancing alters the flow of wealth among
households, financial intermediaries, and investors and
can have both positive and negative implications for the
economy. Homeowners clearly benefit: by refinancing
their mortgages at a lower rate, they often realize substantial savings. For example, consider the homeowner
who pays a fixed rate of 8 percent on a thirty-year mortgage of $200,000. If market rates on mortgages fall to
7 percent, then this homeowner could reduce his or her
monthly mortgage payment from $1,468 to $1,331 by
refinancing at the lower rate. While the transaction
costs of refinancing partly offset this gain, the household savings over the life of the mortgage could be
considerable. In turn, such savings could help boost
consumer spending on goods and services.
Offsetting these benefits, however, are the costs to
mortgage lenders. When a large number of borrowers
refinance, banks and thrifts that own mortgages and
investors in mortgage-backed securities such as mutual

CURRENT ISSUES IN ECONOMICS AND FINANCE

was disproportionately large. After mortgage contract
rates dropped 100 basis points—a relatively modest
decline of l percentage point—between April 1997 and
January 1998, refinancing activity jumped. Refinancings moderated somewhat in the spring of 1998 when
rates leveled off, but a further rate decline of about
35 basis points prompted another, sharper spike in refinancing activity during the second half of the year.

funds will see a decline in investment yields. Consequently, these investors may cut back on other financial
outlays to compensate for potential losses in the mortgage market.
Surges in mortgage refinancings can also lead to
reallocations of income within the financial services
industry. Mortgage servicers typically earn fee income
based on the size of existing loan pools. When old mortgages are prepaid as part of the refinancing process,
loan pools will shrink, causing the service fee income
from these loans to decline.2 By contrast, some participants in the mortgage market—including mortgage
bankers and other originators, loan underwriters, and
distributors of new mortgage-backed securities—may
earn higher fees when refinancing applications rise.

Chart 1 shows that during the first half of the 1990s,
rate declines comparable in size to those in 1997 and
1998 touched off smaller bursts of refinancing activity.
The break with this earlier pattern raises an important
question: If the interest rate savings available to homeowners in 1998 were not exceptional, why was mortgage refinancing activity so vigorous? The answer
requires an understanding of the important role played
by the distribution of rates on outstanding mortgages.

Mortgage Interest Rates and the 1998
Refinancing Surge
Although certain mortgage market participants realize
benefits from refinancing, the most important factor
driving refinancing activity is the potential interest savings accruing to homeowners. The close connection
between market interest rates and refinancing activity
is apparent in Chart 1, which plots the average contract
rate for new thirty-year fixed rate mortgages against an
index of refinancing applications produced by the
Mortgage Bankers Association.3 We see that throughout the 1990s, each decline in rates precipitated a rise
in refinancing activity.

The Changing Distribution of Existing Mortgage Rates
Homeowners typically refinance a fixed rate mortgage
if the rate they pay exceeds the rate available on new
mortgages by 50 to 200 basis points—that is, by ½ to
2 percentage points. 4 Mortgages that meet this refinancing threshold, or a more narrowly defined threshold, can be called “in-the-money.” Thus, in aggregate,
how much refinancing activity follows a given rate
drop depends largely on the proportion of homeowners
whose loans are in-the-money after the interest rate
adjustment.

For most of the decade, the increases in refinancing
applications were commensurate in size with the
decline in interest rates that triggered them. In 1998,
however, the response of refinancing to rate declines

The distribution of rates on outstanding mortgage
loans changes substantially over time (Chart 2). At the
end of 1991, most mortgage loans held rates of about
10 percent, the prevailing interest rate at the time that
these loans were originated in the 1980s.5 As mortgage
rates fell over most of the next two years, a series of
refinancing waves followed, peaking in the fall of 1993.
The concentration of loans in the 10 percent neighborhood was largely eliminated by the 1992-93 refinancings, and the distribution of existing coupons was much
flatter by the end of that year.

Chart 1

Mortgage Rates and Refinancings
Refinance index (March 1990 = 100)
3500

Percentage points
11

Refinancing
applications

Average contract rate
for thirty-year fixed
rate mortgages

10

3000

Scale

After 1993, new loans were originated for several
years in the 7 to 9 percent range, eventually resulting in
a denser concentration of coupon rates. By the end of
1997, an estimated 83 percent of mortgage loans fell in
the 7.25 to 8.75 percent range, and 53 percent carried
rates between 7.50 and 8.25 percent. As market rates
on new thirty-year fixed rate loans dropped toward
7 percent in January 1998, the spread between the market rates and rates on most outstanding mortgages
entered the 50-to-200-basis-point range that normally
triggers refinancing. As a result, refinancings rose to
record highs.

2500

Scale

9

2000
1500

8

1000
7
500
0

6
1990

91

92

93

94

95

96

97

98

Sources: Mortgage Bankers Association; Federal Housing Finance Board.

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2

To illustrate the link between the distribution of
mortgage rates and the number of refinancings, we plot
existing mortgages that are in-the-money alongside

aggregate refinancing activity (Chart 3). For simplicity,
we measure in-the-money mortgages as the percentage
of outstanding thirty-year loans with rates exceeding
the current market rate by at least 100 basis points, or
1 percentage point. 6 Once again, our measure of refinancing is the Mortgage Bankers Association index of
refinancing applications. As the chart shows, the two
series track each other’s movements very closely,
suggesting that a strong relationship exists between the
distribution of existing mortgages that are cost effective
to refinance and aggregate refinancing activity.

Chart 2

Distribution of Outstanding Thirty-Year Fixed Mortgage
Rates, 1991-98
Percent of total outstanding
30
Fourth-quarter 1991
25

30
25

20

20

15

15

10

10

5

5

0

0

25

25

Fourth-quarter 1993

20

20

15

15

10

10

5

5

0

0
25

25

Because changes in interest rates motivate most
homeowner decisions to refinance, we first estimate a
simple model (Model 1) relating refinancing activity to
an interest rate spread, measured as the average thirtyyear contract rate offered in the primary market less the
median interest rate on outstanding thirty-year fixed
rate mortgages. 9 The model estimates confirm that
this mortgage spread is a key determinant of refinancing, explaining about 72 percent of this activity in the
1990-98 period.

Fourth-quarter 1995

20

20

15

15

10

10

5

5

0

0

30

Fourth-quarter 1997

30

25

25

20

20

15

15

10

10

5

5

0

0

35

Statistical Models of Aggregate Refinancing
To assess the relationship between refinancings and
the distribution of mortgage rates more precisely, we
estimate a series of statistical models of aggregate
refinancing activity from 1990 to 1998 (see table).7 The
models allow us to measure the degree to which the
interest rate spread, the distribution of existing
mortgage coupons, and other factors can explain refinancing activity.8

We then include the distribution of existing mortgage interest rates as measured by two variables—the

Chart 3

In-the-Money Mortgages and Refinancings
Refinance index (March 1990 = 100)
2500
Refinancing
applications
2000
Scale

Percent
125

Fourth-quarter 1998

30

In-the-money
thirty-year MBS

100

25

Scale

20
75

1500

50

1000

25

500

15
10
5
0
6.25 6.75 7.25 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25 11.75 12.25

Coupon rate

0

0
1990

Source: Bloomberg L.P.
Notes: Coupon rates on the horizontal axis are adjusted to correspond to the
contract mortgage rates actually paid by households on thirty-year Fannie Mae,
Ginnie Mae, and Freddie Mac loans. Each bar sums two consecutive quarter-point
coupon levels, with only the higher coupon listed.

91

92

93

94

95

96

97

98

Note: In-the-money thirty-year MBS is the percentage of existing thirty-year
mortgage-backed securities issued by government agencies (Fannie Mae,
Ginnie Mae, and Freddie Mac) that have interest rates at least 100 basis
points above the current thirty-year contract rate.

3

CURRENT ISSUES IN ECONOMICS AND FINANCE

percentage of in-the-money mortgages and the percentage of newly in-the-money mortgages (Model 2).10 The
latter variable, calculated as the change in the percentage of in-the-money mortgages from the preceding
quarter, is designed to capture the surge in refinancing
that occurs when an especially large number of mortgages have just become economical to refinance and
many homeowners take action immediately. Both concentration variables have a positive and statistically
significant effect on refinancing, and together they
improve our model predictions about 5 percent.
Moreover, the two concentration variables claim some
of the explanatory power attributed to the spread variable in the simple model. 11 Overall, the interest rate
spread and the distribution of rates together appear to
explain about 77 percent of the refinancing activity.

the existence of a high proportion of moderately
seasoned mortgages could help fuel refinancing activity following an interest rate drop.
Evidence of the importance of seasoning can be
found by comparing mortgage market developments in
1995 with those in 1998 (Chart 1). One reason that
refinancing activity may have remained so mild in 1995
is that a heavy bout of refinancing had just occurred
two years earlier. Given the heavy wave of lending in
1993, many outstanding loans in 1995 would have been
fairly new and thus less likely to be refinanced. By late
1997, however, these same loans would have become
moderately seasoned and may have contributed to the
high level of 1998 refinancing activity.

In Model 3, we introduce the unemployment rate as
an indicator of the state of the economy. Our hypothesis
is that refinancings may have responded so strongly to
interest rate incentives because the overall economy
was strong. Solid employment prospects could help
boost home prices, borrower creditworthiness, and
lender confidence, leading previously cautious borrowers to refinance. Our results confirm the link between
favorable economic conditions and refinancing: adding
the unemployment rate raises the model’s explanatory
power another 7 percent.12

In Model 4, we test the effect of seasoning by separating the mortgage loans in our sample into two
categories—those that are seasoned and those that are
new or moderately seasoned. (Unfortunately, our data
do not permit us to distinguish new from moderately
seasoned loans.) We then calculate in-the-money mortgages and newly in-the-money mortgages for each of
the two categories. We estimate our full model, which
includes the interest rate spread, the unemployment
rate, and separate measures of in-the-money and newly
in-the-money mortgages for both seasoned mortgages
and new and moderately seasoned mortgages.

Finally, we examine the role of mortgage seasoning
in the 1998 refinancing wave. Seasoning is defined as
the amount of time since a loan was originated. Other
factors equal, unseasoned loans (loans two years or
less from origination) and seasoned loans (loans more
than five years from origination) are less likely to be
refinanced than moderately seasoned loans. 13 Thus,

Our results support the conclusion that the level of
refinancing activity is affected by the seasoning of
mortgage loans. For new and moderately seasoned
loans, the concentration variables have a significant
effect on refinancing, while for seasoned loans, these
variables show no significant effects. Thus, it appears
that the rate distribution for new and moderately

Refinancing Models
Spread

Measures of Mortgage Coupon Concentration
In-the-Money Mortgages
Newly in-the-Money Mortgages

Unemployment Rate

Adjusted R2

Model 1

-1.326***
(0.120)

—

—

—

0.72

Model 2

-0.6981***
(0.2152)

0.0187**
(0.0081)

0.0163**
(0.0065)

—

0.77

Model 3

-0.4259*
(0.2400)

0.0401***
(0.0096)

0.0118**
(0.0060)

-0.8423***
(0.2033)

0.84

Model 4

-0.6209**
(0.2286)

-0.8219***
(0.1293)

0.86

N&M
0.0390***
(0.0072)

Seasoned
-0.0103
(0.0071)

N&M
0.0136**
(0.0059)

Seasoned
-0.0071
(0.0080)

Notes: All regressions were run using quarterly data from third-quarter 1990 to third-quarter 1998. N&M—new and moderately seasoned mortgages—consist of mortgages that
are five years or less from origination. Seasoned mortgages are those that are more than five years from origination. Newey-West standard errors appear in parentheses. Standard
tests suggested no significant serial correlation in the error terms.
*Statistically significant at the 10 percent level.
**Statistically significant at the 5 percent level.
***Statistically significant at the 1 percent level.

4

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Chart 4

economically advantageous. Combined with the effects
of a strong economy, the high concentration of outstanding loans—particularly moderately seasoned
loans—that suddenly met this threshold explains why
refinancings rose so quickly and persisted at such high
levels in 1998.

Comparison of Model Performances
Refinance index (March 1990 = 100)
2000

Actual refinance index

1500
Full model

Notes

1000
Simple model

1. For instance, see “A Market That Quivers as Refinancings Rise,”
New York Times, February 8, 1998, late edition; LEX Comment,
Financial Times, February 5, 1998; “Unlike `93, Current Wave of
Refinancings Hasn’t Rocked MBS Market—Yet,” Investor Dealers’
Digest, January 26, 1998; and “Refinancing Boom Is Year Long
Affair,” National Mortgage News, October 12, 1998.

500

0
1996

1997

1998

Notes: The chart compares the actual values of the Mortgage Bankers
Association Refinance Index with the values predicted by the statistical models
described in the text. The simple model (Model 1) includes the interest rate
spread, a time trend, and a constant. The full model (Model 4) includes the
concentration variables adjusted for seasoning, the unemployment rate, a time
trend, and a constant.

2. Consider, for example, the losses associated with early 1998
refinancings, discussed in National Mortgage News (1998).
Servicing rights agreements entitle servicers to a payment equal to a
set percent (for example, 0.5 percent) of an outstanding mortgage
pool (not unlike interest). The value of these rights declines as mortgage prepayments rise. Similarly, investors in interest-only components of collateralized mortgage obligations suffer losses when a
pool of loans prepays rapidly because the anticipated interest to be
paid over the life of the pool decreases.

seasoned mortgages accounts for all of the significance
attributed to concentration in the earlier regressions.

3. The seasonally adjusted Mortgage Bankers Association
Refinance Index is constructed from a weekly survey of applications to refinance existing mortgages. Conducted since 1990, the
survey covers about 40 percent of the residential real estate market
in the United States; respondents include mortgage bankers, commercial bankers, and thrifts. A complete description of the index is
available in “Weekly Mortgage Application Survey, Description,
Indexes and Interest Rates,” March 22, 1995, Mortgage Bankers
Association, Washington, D.C.

Chart 4 illustrates the gain in explanatory power that
comes with the full model and confirms the importance
of rate concentration and a buoyant economy in explaining the dramatic 1998 rise in mortgage refinancing. The
simple model, relying exclusively on the rate spread,
predicts a substantially smaller increase in refinancing
in 1998 than actually occurred. But with the addition of
the two measures of concentration and the unemployment rate, the model tracks the course of last year’s refinancing activity more closely.14 The full model captures
most of the surge in the first quarter of the year, when
the large concentration of loans clustered in the 7.50 to
8.25 percent rate range became cost effective to refinance. It also captures the drop-off in refinancing in the
second quarter, after the most responsive households
had acted. Finally, it does a better job than the simple
model in predicting the high level of refinancing activity
in the third quarter of the year. While a modest decline in
interest rates during this quarter boosted refinancings,
the effects of concentration and a persistently low unemployment rate helped to keep refinancing activity robust.

4. See Follain, Scott, and Yang (1992) for a simulation model
analysis of the optimal rate gap for refinancing. Bennett, Peach,
and Peristiani (1998b) present a statistical analysis of the size of
the rate gap that prompted refinancing in the 1984-94 period, conditional on credit, home equity, market volatility, and other
variables.
5. The data in Chart 2 measure the size of pass-through mortgagebacked securities of the three large government-related mortgage
agencies—Fannie Mae, Ginnie Mae, and Freddie Mac. These securities pass homeowner payments of interest and principal—net a servicing charge of about 50 basis points—through to investors. A large
portion of, but not all, home loans qualify for inclusion in agency
pools. Nevertheless, common interest rate swings affect all borrowers; thus, the shape of the distribution of existing agency security
rates should be reasonably representative of the distribution of outstanding rates paid by all borrowers on thirty-year fixed rate loans.

Conclusion
What accounts for the unexpected strength of mortgage
refinancing activity in 1998? At the end of 1997, a very
large proportion of existing mortgages—many of which
had been originated within the past five years—had
rates slightly above market rates. As interest rates fell in
1997 and 1998, the spread between the rates on these
existing mortgages and the rates available on new mortgages widened to the point where refinancing became

6. This estimate is consistent with recent work on incentives to
refinance. For example, see Follain, Scott, and Yang (1992) and
Bennett, Peach, and Peristiani (1998b).
7. In all of the regression models reported in the table, the dependent variable is the ratio of the Mortgage Bankers Association index
of refinancing applications to the number of owner-occupied homes
with outstanding residential mortgages. The data on the number of

5

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CURRENT ISSUES IN ECONOMICS AND FINANCE

outstanding residential mortgages are from the U.S. Census
Bureau’s American Housing Survey. Because this survey is conducted biannually, we created quarterly observations on the stock of
mortgages by interpolating data using a cubic spine technique.

unemployment rate was generally declining during the 1990s, it
appears to be picking up both the effects of improved economic
conditions on refinancings as well as the general increase in refinancing activity.

8. Each model listed in the table also includes a constant term and
a time trend. The time trend variable, which captures the general
increase in the propensity to refinance existing mortgages over
time, is statistically significant in most regressions. Previous studies, such as Bennett, Peach, and Peristiani (1998a), suggest that this
increased propensity may reflect lower transaction costs and
increased competitiveness among mortgage-lending institutions.
In addition to estimating the four models reported in the table,
we experimented with models that incorporated interest rate volatility and home price appreciation—two variables that previous
studies, such as Caplin, Freeman, and Tracy (1997) and Peristiani
et al. (1997), have shown to affect refinancings. These models are
not reported because in our aggregate-level equations neither
variable is statistically significant and their exclusion did not significantly affect the coefficients on the other explanatory variables.

13. For a discussion of the effect of seasoning on refinancing, see
Richard and Roll (1989) or Fabozzi and Modigliani (1992, p. 208).

9. The median rate is the rate in the middle of the distribution of
existing thirty-year fixed rate mortgages in Fannie Mae, Ginnie
Mae, and Freddie Mac mortgage pools. For skewed distributions—
such as the distribution of outstanding mortgage coupons shown in
Chart 2—the median, rather than the average, may be a better measure of the “center” of the distribution.
10. We define in-the-money mortgages as loans exceeding the
market rate by at least 100 basis points. In our regressions, we tried
several alternative thresholds ranging from 50 to 200 basis points.
Assuming a 150-basis-point threshold produced results very similar
to those reported in the table. Using 50- and 200-basis-point thresholds produced results that differed somewhat from the results
reported in Table 1 but that had the expected sign and were statistically significant.
11. This conclusion is based on a comparison of the coefficients
and standard errors on the spread variable in the two models. The
addition of the concentration variables in Model 2 reduces, but does
not eliminate, both the economic and the statistical importance of
the spread variable.
12. Adding the unemployment rate to our model does, however,
make the time trend variable statistically insignificant. Because the

14. The model also successfully predicts the 1992-93 surge in refinancing activity, although this episode is not shown in the chart.

References
Bennett, Paul, Richard Peach, and Stavros Peristiani. 1998a.
“Structural Change in the Mortgage Market and the Propensity
to Refinance.” Federal Reserve Bank of New York Staff
Reports, no. 45 (September).
———. 1998b. “Implied Mortgage Refinancing Thresholds.”
Federal Reserve Bank of New York Staff Reports, no. 49
(October).
Caplin, Andrew, Charles Freeman, and Joseph Tracy. 1997.
“Collateral Damage: How Refinancing Constraints Exacerbate
Regional Recessions.” Journal of Money, Credit, and Banking,
December: 496-516.
Fabozzi, Frank J., and Franco Modigliani. 1992. Mortgage and
Mortgage-Backed Securities Markets. Boston: Harvard
Business School Press.
Follain, James R., James O. Scott, and T. L. Tyler Yang. 1992.
“Microfoundations of a Mortgage Prepayment Function.”
Journal of Real Estate Finance and Economics 5: 197-217.
National Mortgage News. 1998. July 13, p. 1.
Peristiani, Stavros, Paul Bennett, Richard Peach, Gordon Monsen,
and Jonathan Raiff. 1997. “Effects of Household Creditworthiness on Mortgage Refinancings.” Journal of Fixed
Income, December.
Richard, Scott F., and Richard Roll. 1989. “Prepayments on FixedRate Mortgage-Backed Securities.” Journal of Portfolio
Management, spring: 73-82.

About the Authors
Paul Bennett is a senior vice president and deputy director of the Research and Market Analysis Group;
Frank Keane is a financial specialist and Patricia C. Mosser an assistant vice president in the Group’s
Capital Markets Function.
The views expressed in this article are those of the authors and do not necessarily reflect the position of
the Federal Reserve Bank of New York or the Federal Reserve System.
Current Issues in Economics and Finance is published by the Research and Market Analysis Group of the Federal
Reserve Bank of New York. Dorothy Meadow Sobol is the editor.
Subscriptions to Current Issues are free. Write to the Public Information Department, Federal Reserve Bank of
New York, 33 Liberty Street, New York, N.Y. 10045-0001, or call 212-720-6134. Current Issues is also available at the
Research and Market Analysis Group’s web site: http://www.ny.frb.org/rmaghome/curr_iss/1999.htm.