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Vol. 8, No. 2 • april 2013­­

DALLASFED

Economic
Letter
When Gauging Bank Capital Adequacy,
Simplicity Beats Complexity
by Michael A. Seamans

It is unclear whether
ratio complexity
enhances the ability to
identify failure and is
better than a simpler
ratio. But a simpler
ratio offers the benefits
of greater transparency
and accountability.

T

he pace of bank failures during the recent financial crisis
reached a level not seen in
nearly 20 years, capturing
the attention of regulators and policymakers—particularly those in search
of the best gauge of institutional stress
that might have reliably foretold of the
difficulties.
The capital ratio, a measure of a
bank’s cushion against losses, is a key
metric, and its adequacy is critical to
bankers, regulators and, ultimately,
taxpayers. Over time, regulatory capital
ratios have evolved along with the shifting landscape of banking, becoming
more complex in an effort to capture
the risks of an increasingly complicated
financial world. This reflects the idea
that because a bank’s risk profile helps
determine the amount of capital it needs,
more complex capital ratios should provide a better assessment of institutional
capital adequacy.
Financial crisis experience suggests
it is unclear whether ratio complexity
enhances the ability to identify failure
and is better than a simpler ratio.1 But
a simpler ratio offers the benefits of
greater transparency and accountability.
Conversely, the presence of more complicated ratios—whatever the measurement
shortcomings—may influence the incentives for engaging in excessive risk taking.

Failed Bank Landscape
Banks are in the business of risk; failure will occur. An environment in which
no banks ever fail is impractical and inefficient.2 Generally, a bank fails when its
capital is so depleted that it can’t meet
its obligations to depositors and other
creditors.
A total of 400 commercial banks failed
from Jan. 1, 2008, to Sept. 30, 2012; 10
more received government assistance
and remained open (Chart 1).3
Relative tranquility preceded this turmoil—from 1994 to 2007, only 62 banks
failed. Although more banks collapsed
during the late 1980s and early 1990s
than in the recent crisis, the sum of the
estimated losses to the Federal Deposit
Insurance Corp. (FDIC) insurance fund
since 2008 exceeds the sum of losses from
1986 (when such data first became available) through 2007.
Beyond direct losses to the FDIC,
failure-driven disruption of financial
services inflicted additional costs—estimated at $10 trillion to $20 trillion for the
2008 crisis.4

Assessing Capital Ratios
To the extent that some believe more
complex capital ratios better capture
future risk, boosting their complexity
theoretically should enhance identification of future financial difficulties.

Economic Letter
Chart

1

Failures Highest Since Banking Crisis of 1980s, Early 1990s

December 2012 dollars (in billions)

Number of bank failures

140

250

Adequate Capitalization

Total assets of failed banks

120

200
100

Estimated FDIC losses of failed banks
150

80
Bank failures

60

100

40
50

20
0

’86

’88

’90

’92

’94

’96

’98

’00

’02

’04

’06

’08

’10

’12

0

NOTE: Assistance transactions excluded. Comprehensive data for estimated FDIC losses are not available prior to 1986 and
for 2012.
SOURCE: Federal Deposit Insurance Corp.

Many of the ratios use a basic measure of bank funding, tier 1 capital—in its
simplest form, equity capital (common
and preferred share equity along with
retained earnings) plus minority interests
in subsidiaries, less ineligible intangible
assets (such as goodwill).5
To measure the value of complexity, we use two different, though similar,
ratios. The relatively simpler tier 1 leverage ratio is tier 1 capital divided by bank
assets. The more involved tier 1 riskbased capital (RBC) ratio is tier 1 capital
divided by assets weighted by their riskiness. In either case, the larger the figure,
the greater an institution’s capacity to
absorb future losses.
Chart 2 displays the median leverage and RBC ratios of failed banks as
they approach failure, compared with
historical medians and the historical fifth
percentiles (representing the 5 percent of
banks with the lowest capital ratios) and
regulatory thresholds. Under regulatory
requirements, banks with both leverage
and RBC ratios of at least 4 percent are
considered adequately capitalized.
The median failed-bank leverage ratio
(black line) in the top panel begins near
the historical median of all banks (blue
line), suggesting little difference in capital
levels between banks failing 12 quarters
later and the median for all banks. By
comparison, the median RBC ratio for
failed banks (bottom panel, black line) is

2

ratio of all banks sooner than the lesscomplex leverage ratio, the RBC ratio
doesn’t clearly distinguish undercapitalized banks during the recent crisis any
sooner than the leverage ratio.8

visibly lower than the historical median
as far back as 12 quarters prior to failure.
It’s questionable, however, whether failed
banks are distinguishable from nonfailed
ones three years before failure because
the presence of the median failed-bank
RBC ratio above the bottom 5 percent of
banks indicates that many banks have
similar capital ratios. Additionally, the
presumed effectiveness of forecasts so far
in advance is very limited.
The median failed-bank leverage ratio
falls into the bottom 5 percent of banks
three quarters before failure.6 The median
RBC ratio of failed banks falls below the
fifth percentile of all banks a quarter
sooner, or a year before failure. (When a
bank breaches a threshold between quarters, the occurrence is noted when the latter quarter’s regulatory reports are filed.)
Conversely, the median leverage ratio for
failed banks falls below the well-capitalized threshold one quarter sooner than
the RBC ratio does. This distinction earns
the leverage ratio a slight advantage by its
ability to identify troubled institutions a
bit earlier using regulatory thresholds.
The median failed bank leverage ratio
and RBC ratio both slip below the adequately capitalized threshold (green line)
just one quarter prior to failure—neither
providing much advance warning of gathering stress.7
Although the median failed banks’
RBC ratio diverges from the median RBC

The likelihood of failure for banks
not meeting “adequately capitalized”
regulatory thresholds provides another
comparative test. In Chart 3, three bars
are shown for each quarter: the number
of banks with leverage ratios below the
existing 4 percent adequately capitalized
threshold (left bar), the number with RBC
ratios below 5.4 percent (center bar) and
the number with RBC ratios less than the
4 percent adequacy measure (right bar).
The 5.4 percent measure is the value at
which an equal number of banks would
fall below the RBC ratio threshold and the
4 percent leverage ratio threshold over
the charted period.
At March 31, 2008, only five banks
(less than 0.1 percent) had leverage ratios
below 4 percent, while three institutions’
RBC ratios fell below that same threshold. Of the 6,610 banks operating in June
2012, 99 banks’ (1.5 percent) leverage
ratios were below 4 percent; 46 banks’
(0.7 percent) RBC ratios were less than
4 percent. The difference in the number
of banks below regulatory thresholds for
the two ratios signals the need for a more
even comparison.
However, comparing the 4 percent
leverage ratio on equal footing with the
5.4 percent RBC ratio doesn’t yield a convincing winner over the four-and-a-halfyear period—59 percent of banks below
the leverage ratio regulatory threshold
ultimately failed versus 61 percent of
banks with RBC ratios below 5.4 percent.

Comparing Regulatory Thresholds
Another way to compare the ratios’
ability to identify bank failures is to set
thresholds for each so the same number of
banks are flagged and then see which ratio
predicts the greatest number of failures
over the following year. In this case, the
lowest 2.5 percent and 5 percent of each
ratio as of June 30, 2009, were monitored
over the four-quarter period between third
quarter 2009 and second quarter 2010.9
Looking at the bottom 2.5 percent,
the leverage ratio included 66 percent

Economic Letter • Federal Reserve Bank of Dallas • April 2013

Economic Letter
of the banks that failed in the following
four quarters and the RBC ratio captured
64 percent of the bank failures. In short,
both identified about two-thirds of pending bank failures. Looking at the worst 5
percent, the leverage ratio captured 76
percent of failed banks, the RBC ratio 80
percent. Again, neither ratio stands out as
a clear winner.

Chart

Changes in Leverage, Risk-Based Capital Ratios
Precede Failures

2

Percent

Leverage ratio

10
8
6
4
2

Predictive Power
The two ratios’ accuracy is tested in
Chart 4, identifying banks that failed or
received assistance within four quarters
(solid lines) or eight quarters (dashed
lines) over a full range of hypothetical
thresholds.10 The vertical axis measures
the percentage of missed alarms (failed
banks identified as nonfailed)—in statistical terms, the type I error rate. The horizontal axis measures the percentage of
false alarms (nonfailed banks identified
as failed), the statistical type II error rate.
The performance of the two capital ratios when the percentage of false
alarms/type II errors is low is of particular
interest because a tradeoff in efficiency
arises when a reduction of missed alarms
comes at the expense of misclassifying
more surviving banks. Focusing on a low
type II error rate enables comparison of
the number of failures missed (type I error
rate) for a given sample number of banks
that each ratio misclassified as failures.
Both ratios are quite successful at
detecting bank failures four quarters in
the future (solid lines). At the 5 percent
false alarm/type II error rate, the leverage ratio correctly classifies 77 percent of
failures (misclassifies 23 percent) and the
RBC ratio correctly classifies 79 percent of
failures (misclassifies 21 percent).
As one might expect, the ability to identify failed banks decreases with an increase
in the forecast horizon. For example, at the
eight-quarter horizon (dashed lines) and
5 percent false alarm/type II error rate,
the RBC ratio correctly classifies 57 percent (misclassifies 43 percent) of failures,
whereas the leverage ratio correctly identifies 51 percent (misclassifies 49 percent).
While the difference in predictive power
increases at a 10 percent false alarm/type
II error rate over eight quarters, the leverage ratio is 7.5 percent and the RBC ratio
is 9.75 percent at this error rate—both outside existing regulatory thresholds.

0

12

14
12
10
8
6
4
2
0

11

10

9

8

7

6

5

4

3

2

1

0

4

3

2

1

0

Risk-based capital ratio

12

11

10

9

8

7
6
5
Quarters prior to failure

Failed-bank median
5th percentile of all banks, 2000–04*
Median of all banks, 2000–04*
Adequately capitalized threshold
Well-capitalized threshold**
* The median and fifth percentile values are constants calculated using the five-year period preceding the analysis window
and include all commercial banks from first quarter 2000 through fourth quarter 2004. Failed-bank medians include banks
that failed between first quarter 2008 and third quarter 2012.
**To be considered well capitalized, banks must have a tier 1 leverage ratio of 5 percent or more, a tier 1 risk-based capital
ratio of 6 percent or more and a total risk-based capital ratio of 10 percent or more.
SOURCES: Federal Deposit Insurance Corp.; Reports of Condition and Income, Federal Financial Institutions Examination
Council; author’s calculations.

Chart

3

Both Ratios Identify a Similar Number of Failed Banks
When Placed on Even Footing

Number of banks
140

120

100

80

60

Failed more than 4 quarters later

Failed within 4 quarters
Tier 1 riskbased capital
ratio < 5.4%
(center bar)

Nonfailed

Tier 1 riskbased capital
ratio < 4%
(right bar)

Tier 1
leverage
ratio < 4%
(left bar)

40

20

0

Q1

Q2 Q3
2008

Q4

Q1

Q2 Q3
2009

Q4

Q1

Q2 Q3
2010

Q4

Q1

Q2 Q3 Q4* Q1* Q2*
2011
2012

* The most recent three quarters do not include a full four quarters of failures.
SOURCES: Federal Deposit Insurance Corp.; Reports of Condition and Income, Federal Financial Institutions Examination
Council; author’s calculations.

The portion of the chart corresponding
to current regulatory minimums is where
the false alarm/type II error rate is very

low and both ratios have a similarly high
missed alarm/type I error rate. If the false
alarm/type II error rate at the eight-quarter

Economic Letter • Federal Reserve Bank of Dallas • April 2013

3

Economic Letter

Chart

4

Both Capital Ratios Exhibit Similar Success in Predicting
Bank Failures with Respect to Regulatory Minimums*

Missed alarm rate** (bank failed but not identified)

100
90
80
Tier 1 leverage ratio (failed within 8 quarters)
Tier 1 risk-based capital ratio (failed within 8 quarters)
Tier 1 leverage ratio (failed within 4 quarters)
Tier 1 risk-based capital ratio (failed within 4 quarters)

70
60
50
40
30
20
10
0
0

See “Ending ‘Too Big to Fail’: A Proposal for Reform Before
It’s Too Late,” speech by Richard W. Fisher, Jan. 16, 2013.
3
Commercial banks, or more simply “banks” in this article,
are Federal Deposit Insurance Corp.-insured commercial
banks, state savings banks and cooperative banks.
4
See “Leveling the Playing Field,” by Harvey Rosenblum, in
“Financial Stability: Traditional Banks Pave the Way,” Federal
Reserve Bank of Dallas Special Report, Jan. 29, 2013, http://
dallasfed.org/microsites/fed/annual/2012/indexw.cfm.
5
More formally, tier 1 capital is composed of total bank
equity capital (which includes common stock, perpetual
preferred stock and related surplus, retained earnings and
accumulated other comprehensive income) plus qualifying minority interests in consolidated subsidiaries, less
nonqualifying perpetual preferred stock, goodwill, other
disallowed intangible assets and any other amounts that are
deducted in determining tier 1 capital in accordance with
regulatory capital standards.
6
The fifth percentile was selected because about 5 percent
of banks at the end of 2007 failed between Jan. 1, 2008, and
Sept. 30, 2012.
7
In response to the crisis, the proposed Basel III tier 1
risk-based capital threshold for a bank to be adequately
capitalized was set at 6 percent. Using this threshold for the
tier 1 RBC ratio, the failed bank median also falls below the
threshold at one quarter prior to failure.
8
When revised capital ratios are compared with the realtime capital ratios used in this analysis, the incidence of
downward adjustments is higher for banks that ultimately
failed. Tier 1 risk-based capital ratios are generally revised
more frequently than tier 1 leverage ratios.
9
Second quarter 2009 was used as an example because it
provides the greatest number of bank failures in the following four quarters.
10
The same type I, type II error rate analysis was also
performed for both ratios to compare their predictive power
in identifying failures within 12 quarters prior to failure, but
it was not charted. Neither ratio proves to be very accurate as
the window is increased to 12 quarters.
2

10

20

30

40

50

60

70

80

90

100

False alarm rate** (bank identified but did not fail)
* Successful predictions for a given quarter are defined as banks that failed or received assistance in the following four or
eight quarters. Analysis includes banks that failed between Jan. 1, 2008, and Sept. 30, 2012.
**Missed alarm rate refers to the type I error rate. False alarm rate refers to the type II error rate.
SOURCES: Federal Deposit Insurance Corp.; Reports of Condition and Income, Federal Financial Institutions Examination
Council; author’s calculations.

horizon is set at a level that includes banks
with leverage ratios below 4 percent, the
type II error rate is 0.17 percent and the
corresponding type I error rate is 79 percent. For the RBC ratio, the type II error
rate is 0.06 percent and the type I error rate
is 86 percent. The extremely low type II
error rates indicate that there is little difference in the performance of the two ratios
with respect to the regulatory minimums.
While both the tier 1 risk-based capital
ratio and tier 1 leverage ratio help predict
future bank failures, the more complex
tier 1 RBC ratio does not markedly outperform the simpler tier 1 leverage ratio and,
at times, underperforms it. In essence,
greater capital ratio complexity doesn’t

DALLASFED

make the task of identifying future bank
failures any easier.
Seamans is a financial industry analyst in
the Financial Industry Studies Department
at the Federal Reserve Bank of Dallas.

Notes
For more information on the topic, see “The Dog and the
Frisbee,” by Andrew G. Haldane and Vasileios Madouros,
Bank of England, paper presented at “The Changing Policy
Landscape” symposium sponsored by the Federal Reserve
Bank of Kansas City, Jackson Hole, Wyo., Aug. 30–Sept. 1,
2012; and “Capital Ratios as Predictors of Bank Failures,”
by Arturo Estrella, Sangkyun Park and Stavros Peristiani,
Federal Reserve Bank of New York Economic Policy Review,
July 2000.

1

Economic Letter

is published by the Federal Reserve Bank of Dallas. The
views expressed are those of the authors and should not
be attributed to the Federal Reserve Bank of Dallas or the
Federal Reserve System.
Articles may be reprinted on the condition that the
source is credited and a copy is provided to the Research
Department of the Federal Reserve Bank of Dallas.
Economic Letter is available free of charge by writing
the Public Affairs Department, Federal Reserve Bank of
Dallas, P.O. Box 655906, Dallas, TX 75265-5906; by fax
at 214-922-5268; or by telephone at 214-922-5254. This
publication is available on the Dallas Fed website,
www.dallasfed.org.

Richard W. Fisher, President and Chief Executive Officer
Helen E. Holcomb, First Vice President and Chief Operating Officer
Harvey Rosenblum, Executive Vice President and Director of Research
E. Ann Worthy, Senior Vice President, Banking Supervision
Mine Yücel, Vice President and Director of Research Publications
Anthony Murphy, Executive Editor
Michael Weiss, Editor
Jennifer Afflerbach, Associate Editor
Ellah Piña, Graphic Designer

Federal Reserve Bank of Dallas
2200 N. Pearl St., Dallas, TX 75201