© 2022 International Monetary Fund
WP/22/153
IMF Working Paper
Strategy, Policy and Review Department
Understanding and Predicting Systemic Corporate Distress: A Machine-Learning Approach
Prepared by Burcu Hacibedel and Ritong Qu*
Authorized for distribution by Martin Cihak and Daria Zakharova
July 2022
IMF Working Papers describe research in progress by the author(s) and are published to elicit
comments and to encourage debate. The views expressed in IMF Working Papers are those of the
author(s) and do not necessarily represent the views of the IMF, its Executive Board, or IMF management.
ABSTRACT:
In this paper, we study systemic non-financial corporate sector distress using firm -level probabilities of default
(PD), covering 55 economies, and spanning the last three decades. Systemic corporate distress is identified by
elevated PDs across a large portion of the firms in an economy. A machine-learning based early warning
system is constructed to predict the onset of distress in one year’s time. Our results show that credit expansion,
monetary policy tightening, overvalued stock prices, and debt-linked balance-sheet weaknesses predict
corporate distress. We also find that systemic corporate distress events are associated with contractions in
GDP and credit growth in advanced and emerging markets at different degrees and milder than fina ncial crises.
JEL Classification Numbers:
C40, E44, G01, G17, G21, G33
Keywords:
Nonfinancial sector; Probability of default; Early warning system s;
Macroprudential policy
Author’s E-Mail Address:
bhacibedel@imf.org, rqu@imf.org
* The views expressed in this paper are those of the author(s) and do not necessarily represent the views of
the IMF, its Executive Board, or IMF management. We would want to thank Bruno Albuquerque, Jorge Antonio
Chan-Lau, Sophia Chen, Salih Fendoglu, Marco Gross, Weining Xing and seminar participants at the IMF for
helpful comments; Chuqiao Bi, Ruofei Hu, Roshan Iyer and Jose Marzluf for excellent research assistance.
Special thanks to Bruno Albuquerque for helping us understand Compustat data. All the erro rs are our own.
©International Monetary Fund. Not for Redistribution
Contents
1 Introduction
3
2 Data
2.1 Constructing Economy-level PD Indices . . . . . . . . . . . . . . . . .
2.2 Predictors of Systemic Corporate Distress . . . . . . . . . . . . . . .
5
6
7
3 Identifying Corporate Sector Distress
3.1 A Markov-Switching Model for PD Indices . . . . . . . . . . . . . . .
3.2 Model Estimates and Periods of High Corporate Sector Distress . . .
8
9
10
4 An
4.1
4.2
4.3
4.4
11
12
13
14
16
Early-warning System for Corporate Distress
Model Combination . . . . . . . . . . . . . . . . . . . .
H-block Cross-validation . . . . . . . . . . . . . . . . .
Model Performance . . . . . . . . . . . . . . . . . . . .
Interpreting Model Predictions with Shapley Values . .
4.4.1 An Application: Corporate Distress Risk Index
Markets . . . . . . . . . . . . . . . . . . . . . .
. .
. .
. .
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for
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. . . . . .
Emerging
. . . . . .
18
5 Macroeconomic Implications of Systemic Corporate Distress: Initial
19
Findings
6 Conclusion
21
Tables and Figures
25
Appendix A MCMC Algorithm to Identify Corporate Distress
39
Appendix B Constructing Predictors from Compustat Global
40
Appendix C Machine Learning Models and Hyperparameter Selection
C.1 Logistic Regression with Regularization . . . . . . . . . . . . . . . . .
C.2 Random Forest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C.3 Support Vector Machine . . . . . . . . . . . . . . . . . . . . . . . . .
C.4 Linear Discriminant Analysis . . . . . . . . . . . . . . . . . . . . . .
C.5 Extreme Gradient Boosting Tree . . . . . . . . . . . . . . . . . . . .
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41
41
42
43
44
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1
Introduction
The Covid crisis and resulting vulnerabilities brought the corporate sector to the forefront of policy debate. Many governments supported corporations through monetary,
fiscal and financial policies such as low interest rates, grants, and debt moratoria.
Corporations are coming out of the pandemic with higher debt, lower profitability,
weaker balance sheets and lower cash buffers (IMF, 2021). In the post-Covid period,
the withdrawal of support measures could increase the risk of corporate distress, potentially leading to systemic crises. In this context, the ability to predict corporate
distress and understand its macroeconomic consequences is key. Timely detection of
the sources of corporate vulnerability beyond general indebtedness enables a more
targeted policy choice.
This paper aims to provide an early warning system to forecast corporate distress
events to inform timely policy making. We first identify these events using a novel
measure and definition based on firm-level probabilities of default (PD) covering the
last three decades 1995:2021. Our new measure allows us to take a deeper look at
how the corporate sector and economic indicators behave before corporate distress.
We build an ensemble of machine-learning models drawing on a set of macroeconomic
and balance-sheet variables to predict the onset of systemic corporate distress over
a four-quarter horizon. Rather than selecting the best model in a horse race, we
take an agnostic view that none of each individual model is the true model, and try
to approximate the true model using the combination of individual models (Geweke
and Amisano, 2011). Our model not only predicts the approaching distress, but
also offers hints about the sources of corporate vulnerability. Our results show that
weak balance sheets and global financial conditions play a large role in predicting
corporate distress. These allude to the importance of timely use of monetary and
macroprudential policies.
There are several challenges to empirical studies of corporate distress. Existing
literature lacks a consistent definition of corporate crises or distress. While these two
terms are interchangeable, we will use the term “corporate distress” in the remainder
of this paper. The lack of cross-country and longitudinal data on corporate distress
also makes it hard to analyze cause and aftermath of systemic nonfinancial corporate
sector distress. Existing studies are mostly single-country or single-crisis episode
focused such as Japan in the 1990s (Caballero et al., 2008), Europe in the 2010s
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(Schivardi et al., 2022; Acharya et al., 2020), US (Giesecke et al., 2014), and the issue
of corporate crises has not been studied in a long-run cross-country setting so far.
With our new definition, we are able to overcome this roadblock. Another major
challenge is the intertwined nature of corporate distress with other economic crises.
It is hard to find a corporate distress example that is not preceded or does not overlap
with crises of other nature such as banking, sovereign debt, and currency crises. In
our paper, we also suggest ways to overcome this difficulty, and conduct robustness
tests accordingly. One caveat of our data is that it covers listed firms only.
Corporate distress has been mostly linked to credit booms and increasing leverage (Jordà et al., 2020; Müller and Verner, 2021; Lian and Ma, 2021)with significant
macroeconomic and microeconomic implications. While there is some consensus on
the relatively benign impact of credit distress on the economy compared to financial
crises (Giesecke et al., 2014), the type of credit matters. Credit booms driven by
corporate and by households affect the economy differently. Household credit driven
booms have been shown to have more significant and long lasting impact on GDP
growth (Jordà et al., 2013; Mian et al., 2017). The underlying credit and credit dynamics matter for the macro impact. Studies focusing on the microeconomic dynamics
and impact focus on the debt overhang and zombification that follow credit booms
leading to lower investment by firms (Andrews and Petroulakis, 2019; Gourinchas
et al., 2020; Albuquerque, 2021).
To measure corporate distress, existing studies use definitions based on corporate credit growth (Jordà et al., 2020), actual defaults (Giesecke et al., 2014) and
distance-to-insolvency (Atkeson et al., 2017)with most in single-country settings. To
our knowledge, we are the first paper to use a default probability based measure. The
model-based PD uses balance-sheet variables, macro factors and distance-to-default
(Merton, 1974) as predictors. Hence, the PD is a comprehensive and timely measure
of a firm’s difficulty in operation, liquidity, and investors’ perception of its underlying
risk. Our PD dataset coming from Corporate Research Initiative of National University of Singapore covers more than 60,000 publicly listed firms from 88 economies.
We construct economy-level PD indices by capital-weighted-average of firm-level
PDs. Periods of systemic corporate sector distress are characterized by persistently
elevated PD indices and identified by a Markov regime-switching model (Hamilton,
1989). We find that economies experienced corporate distress 18 percent of the time
on average over 1995:2021. Many, but not all corporate distress events, overlap with
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documented financial, sovereign debt and currency crises. Notably, we observe a wave
of corporate distress in many economies during the early 2000s that coincides with
the Dot-com bubble, which cannot be attributed to other types of crises.
Our paper contributes to the existing literature in several areas. First, we propose
a new definition for corporate distress and provide a novel database of corporate
distress events covering the last three decades and 55 advanced and emerging markets.
Economies experienced corporate distress 18 percent of the time on average over
1995:2021. However, not all corporate distress events lead to systemic financial crises.
Secondly, we find that systemic corporate distress has implications for GDP and credit
growth. Our results show that around corporate distress, GDP growth slows down
in both AEs and EMs while credit growth slows down significantly only in EMs.
Thirdly, we construct a machine-learning based model to forecast systemic corporate
distress with a forecast horizon of 4 quarters. This allows us to identify indicators
that signal increasing risk of crisis. In addition to over-heating in credit markets, the
model attribution analysis shows that funding costs, balance sheet vulnerabilities and
market overvaluation are also informative about coming corporate crises.
The rest of the paper is structured as follows: Section 2 presents the data and descriptive statistics. Section 3 defines and identifies corporate distress events. Section 4
explains the machine learning based early warning model and examines the precursors
of systemic corporate distress. Section 5 analyzes the contemporary macroeconomic
impact of corporate distress. Section 6 focuses on the policy implications and concludes.
2
Data
We construct our data focusing on two groups: economy-level PD indices and a set of
variables that can predict systemic corporate distress. PD data helps us construct a
novel crisis series to overcome the lack of a broad-based definition of systemic corporate distress. Then, we select predictor variables to proxy for four group of indicators
closely linked to corporate distress: firm-level balance sheet variables, international
macro variables, domestic macro variables and financial market valuation variables.
while we start with a larger set of variables, we eliminate a number of these while
building up our model if not significant. Once we have the crisis/distress dates, we
are able to check for the signaling power of the predictor variables.
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2.1
Constructing Economy-level PD Indices
The quarterly PD data is obtained from the Credit Research Initiative database of
the National University of Singapore (NUS-CRI PD, henceforth)1 . The probability
of a firm defaulting on its debt encapsulates the firm’s difficulty in operation, its
liquidity and investors’ perception of its underlying risk. Hence, the probability of
default (PD) is an apt proxy for corporate distress. PDs are derived from a reduced
form model (Duan et al., 2012) that draws on both market-based, such as distanceto-default (Merton, 1974), and accounting-based firm-specific attributes as well as
macro-financial factors including the stock returns, cash-to-asset ratio, current assetsto-current liabilities ratio, net-income-to-total-asset ratio, relative market cap and
relative market-to-book ratio.The model performs well especially in shorter horizons,
achieving an accuracy ratio of 80% in 12 month forecasts. The data set covers the
daily probability of default of firm-level corporate bonds with maturities up to 5
years. We focus on the default probability of 12-month corporate bonds (excluding
the financial sector),
We construct quarterly economy-level PD indices using capital-weighted averages
of firm-level PD at the end of each quarter. At the beginning of each year, the firmlevel capital is calculated as the product of stock prices and common shares outstanding from Compustat Global. The NUS-CRI PD is matched with Compustat Global
using ISIN. Among the 2,749,611 firm-quarter observations, 2,367,880 are matched
with the firm capital data. Missing capital values are imputed with the median of
other firms’ capital values in the same sector, quarter and from the same economy.
After the imputation, the missing capital values are further imputed with the median
of other firms’ capital values in the same quarter and from the same economy. To
make sure the indices are not biased by any limited coverage of firms, we impose a
minimum of 20 firms for each economy-quarter observation. Table 1 shows the summary statistics of PD indices for each economy. After discarding economy-quarter
observations with insufficient firm coverage, the resulting economy-level average PD
indices covers 61,960 firms from 88 economies. The earliest data starts in March 1990.
For the purposes of this paper, our sample ends in the last quarter of 2021.
1
See The Credit Research Initiative of the National University of Singapore (2019) for a detailed
description of the methodology.
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2.2
Predictors of Systemic Corporate Distress
We draw on the literature to select a total of 43 predictors covering domestic and
international macro economic variables, firm balance sheet variables, lagged PDs and
variables derived from stock prices. Table 2 shows the full list of variables employed.
Balance sheet Variables
A vast literature, e.g., Altman (1968), Ohlson (1980), Shumway (2001) and Campbell
et al. (2008), has shown that firm-level balance-sheet variables can predict corporate
defaults. We include the capital expenditure-to-asset ratio, cash-to-asset ratio, debtto-asset ratio, interest-coverage ratio, net debt-to-asset ratio, return on assets and
short-term investment-to-liability ratio. We also include the 12-month and 36-month
probabilities of default from NUS-CRI. To allow for economy-specific steady state of
PDs when identifying distress periods, we scale the PD series of each economy to
unit variance before feeding into the early warning system. In addition to the levels
of balance-sheet variables, we also include their quarterly changes as predictors. The
balance-sheet variables are obtained from Compustat Global. The details about how
the ratios are computed are provided in Appendix B.
Macroeconomic Variables
Besides the accounting ratios, Carling et al. (2007), Duffie et al. (2007) and Koopman et al. (2012) show that domestic macroeconomic variables can predict corporate
defaults. Pesaran et al. (2006) find global macroeconomic variables also affect default probabilities. We have a total of 11 macroeconomic variables covering various
aspects of the business cycle, credit and external sector. Among these, Fed Funds
Shadow Rate2 and USD appreciation are used as common predictors for corporate
distress events across all economies, reflecting the global financial cycle (Rey, 2015)
and conditions. The list of macroeconomic variables can be found in Panel B of Table
2.
2
The Fed Funds Shadow Rate is from Federal Reserve Bank of Atlanta using the method of Wu
and Xia (2016).
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Market Valuation
Variables related to stock prices are often used to predict defaults, especially when
excessive risk taking and asset bubbles. For example, Campbell et al. (2008) and
Duffie et al. (2007) use returns of the market index as predictors. To reflect this, we
include return volatility, dividend yields and price-earnings ratios because overvalued
stock prices could reflect overheating, mispricing and asset bubble risks in financial
markets
Missing Predictors
Given that we cover a large set of predictors, the issue of missing predictors is inevitable, especially for emerging markets. Figure 6 shows a heat-diagram of predictor
availability over time.The darker the shading is, the larger is the number of economies
for which a specific variable is missing in a given year. The color scale is shown to the
right of each figure. The number is defined as the ratio of the number of economies
for which each predictor is available over the total number of economies. Our sample
starts from 1995Q1. Most of balance sheet variables become broadly available from
1996 onwards.
In the early-warning system for corporate distress introduced in Section 4, missing
predictors are imputed by the sample median when forecasting. To avoid any biased
output, we only include economy-quarter observations where more than two-thirds of
the predictors are available. After imposing the cutoff, we end up with 55 economies
in our early-warning system.
3
Identifying Corporate Sector Distress
The economy-level PD indices constructed in Section 2 serve as proxies for systemic
corporate distress in an economy. They align well with corporate distress periods documented in the literature. The top panel in Figure 1 shows that advanced economies
experienced high level of PDs during the burst of the dot-com bubble in the early
2000s and during the Global Financial Crisis (GFC) in 2008. In addition to these two
episodes of high corporate sector stress, EMs also experienced high PDs during the
Asian Financial crisis in late 1990s. As documented in Das et al. (2007), corporate
defaults happen in time clusters which implies cyclical waves of economy-level PD
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indices. This is exactly what we find in Figure 2 of PD indices for selected economies.
3.1
A Markov-Switching Model for PD Indices
To identify the corporate distress events, we construct a Markov Switching model as
characterized by persistently high PDs. Average PD indices across economy blocks
(the top panel of Figure 1), and individual economy PD (Figure 2) indices show that
the corporate sector is subject to infrequent regimes of high and volatile default probabilities. The Markov Regime-switching model (Hamilton, 1989) is apt for identifying
states of high risk, characterized by persistently high PD indices. One challenge is
that corporate sector distress periods have few observations for each individual economy, which can lead to large estimation errors. To address the issue, we pool model
parameters across different economies to take advantage of the cross-sectional dimension of the data: we can borrow from other economies’ experience to estimate each
economy’s parameters. Pooling the parameters also gives a consistent definition of
corporate sector distress across economies. We assume the ratio of mean PD in high
risk regime to mean PD in low risk regime to be the same across economies. We
make the similar assumption on volatilities. On the other hand, the median level of
PD indices are quite dispersed among economies as shown in Table 1, possibly due
to different industry compositions and legal restrictions pertinent to defaults. For
example, the calm period in Argentina’s corporate sector can have a higher expected
PD than the high-risk regime of Switzerland. To account for differences in steady
states of PDs across economies, we set economy-specific mean and volatility of PDs
in low-risk regimes. and set the ratio of the high-risk regime’s mean and volatility of
PD over those of low-risk regime’s to common parameter across economies.
Before specifying the model, we introduce some notations. Let i denote the economy i, (i ∈ {1, 2, ..., N }) and t denote period t (t ∈ {1, 2, ..., T }). Let Sit ∈ {0, 1}
index two regimes. Sit is driven by a Markov Regime-Switching model:
Prob(Sit = m|Sit−1 = n) = pmn .
(1)
Under each regime, the dynamics P Dit is different in terms of mean and volatility:
P Dit − (1 + δSit ) µiL = ρ (P Dit−1 − (1 + δSit−1 ) µiL ) + (1 + γSit ) σiL εit .
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(2)
µiL is the unconditional mean of P Dit in the low default probability regime. (1 + δ)
is the ratio of high-risk regimes’ unconditional mean over those of low-risk regimes.
We impose the constraint that δ is positive. Similarly, σiL is the volatility of P Dit ’s
innovations in the low default probability regime. (1 + δ) is the ratio of high-risk
regimes’ volatility to those of low-risk regimes. We impose the constraint of 1 +
γ > 0 to make sure the volatility is positive. Parameters δ, γ and ρ are the same
across different time series. By using same parameters, δ and γ, we insure crises
are identified based on same criteria across economies. µiL and σiL are economyspecific to account for economy-specific factors that affect its mean and volatility,
as demonstrated in Table 1. Given the proliferation of parameters in a model of
many economies, maximum likelihood estimates are computationally difficult, so we
estimate the model using Bayesian approach. The MCMC algorithm is elaborated in
Appendix A.
3.2
Model Estimates and Periods of High Corporate Sector
Distress
Both the mean and the volatility of PDs in the high-PD regime are considerably larger
than the ones in the low-PD regime. Table 3 reports the estimates of key parameters
in the Markov Regime-switching model. The mean of PDs during the high-PD regime
is around 3.7 times the ones in low-PD regime. The volatility of innovation in PDs
is also higher in the high-PD regime (around 5.9 times) than in the low-PD regime.
The posterior probability of the corporate distress regime is presented as a heat
map in Panel (a) of Figure 3. We use a threshold of 50% on the posterior probability
of a high-PD regime to identify the distress periods, as shown in Panel (b) of Figure
3. Darker color indicates high posterior probability. We only include economies
with more than 10 years of observations when estimating the model. After imposing
the minimum sample length cutoff, we end up with 66 economies. The full list of
corporate distress periods is in Table A1 in the Appendix, and distress periods with
higher posterior probabilities are also shown here using a different color shading.
With our proposed definition of corporate distress, we can capture several major
corporate distress events documented in the literature. These include the 1995 Mexico
crisis, 1997 Asian crisis, 2000-01 dot-com bubble/burst, 2012 European Debt crisis,
and 2007-08 Global Financial Crisis. Covid-19 also caused high corporate distress in
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many economies starting in 2020. Starting from the late 1990s, both the advanced
economies and emerging markets went through prolonged periods of high corporate
sector distress that ended in the early 2000s. In total, we are able to identify 193
episodes of distress events, and economies experience corporate distress in 18% of the
time on average.
Considering the attention banking crises received in the literature, one natural question is how corporate distress events overlap or differ from banking crises
(Giesecke et al., 2014). Our analysis shows that while many high corporate distress
periods overlap with banking crises, we also identify several episodes of high corporate distress with no overlapping banking crisis. Figure 4 shows corporate distress
periods vs banking crises periods. Corporate distress periods are marked in green;
banking crises are in blue; the overlapping years are in red. Banking crisis identification is borrowed from Laeven and Valencia (2020) with the sample ending in 2017.
Notably, we capture several high corporate distress periods in the early 2000s (the
dot-com bubble) and in the early 2010s (the European debt crisis) with no simultaneous banking crises. Figure 5 also shows corporate distress periods vs external crises
periods. Most external crises are covered by corporate distress periods.
4
An Early-warning System for Corporate Distress
For our early warning system, we build a machine-learning model to predict the onset
of corporate distress periods within a one-year horizon, using the corporate distress
definition in Section 3 and the predictors in Section 2.
Essentially, any sample observation can be classified into three categories: predistress periods, distress periods and calm periods. Because the early-warning system
aims to predict corporate distress in advance, we confine ourselves to differentiating
pre-distress periods from calm periods, and discard the distress periods when estimating and evaluating the model. Let Cit be an indicator function that equals to 1
when a corporate sector distress event in economy i starts at time t. Let Cit+1,t+h
be an indicator function that equals to 1 if a distress event starts between t + 1 and
t + h:
Cit+1,t+h = 1{∀Cis =1,s∈[t+1,t+h]} .
(3)
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The output of the early-warning system is a probability of a corporate distress event
that happens in economy i and starts in the window between t + 1 and t + h, using
predictors at time t,
Prob (Cit+1,t+h = 1|xit ) = f (xit ) .
(4)
The function f in Eq. (4) can be approximated by many functional forms, from linear
logit models to more flexible machine learning methods. We estimate five models of
distinctive functional form including Logit Lasso, linear discriminant analysis (LDA),
support vector machine (SVM), random forest (RF) and extreme gradient boost classifier (XGBoost). These methods are decsribed in detail in the Appendix C.
4.1
Model Combination
Rather than selecting one single model, we combine the five models to proximate
the true data generating process using the optimal pooling approach in Geweke and
Amisano (2011). The method was shown to outperform Bayes model averaging in
out-of-sample forecasting by making a more general and realistic assumption that
none of the candidate models is the true form of f 3 . Let fˆ1 , fˆ2 , ..., fˆM be estimation
of f from M models. Define the final model as weighted average of individual models:
fˆ (x) =
M
X
wm fˆm (x) ,
(5)
m=1
M
X
wm = 1, 0 ≤ wm ≤ 1,
(6)
m=1
where wm is the weight attached to the mth model. The optimal weights would be
the ones that minimize the cross-entropy of the combined model to the true data
generating process. Empirically, we estimate weights by maximizing the likelihood
function
∗
w = arg max
w
T X
N
X
t=1 i=1
(
log
M
X
h
)
i
wm Cit+1,t+h fˆm (xit ) + (1 − Cit+1,t+h ) 1 − fˆm (xit )
.
m=1
(7)
3
For an introduction to Bayes model averaging , see, e.g., Raftery (1995) and Hoeting et al.
(1999). See Gross and Población (2019) for an application of Bayes model averaging to bank stress
testing.
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Given that we aim to minimize the expected cross-entropy out of sample, a caveat is
that xit should not be included in the sample used to estimate fˆm when computing
fˆm (xit ) in equation Eq. (7). We address this issue using cross-validation that is
adapted to the case of panel data at the presence of time series and cross-section
dependence. The next subsection elaborates on the cross-validation method we used.
4.2
H-block Cross-validation
The panel data for pre-distress periods exhibits cross-sectional dependence as is evident in the clustering of economies experiencing corporate distress shown in Panel
(b) of Figure 1 . By the definition of pre-distress periods, the target variable Cit+1,t+h
is also auto-correlated in the time dimension, because the forecast horizon is longer
than one quarter. This violates the independence assumption underlying traditional
leave-k-out cross-validation. We adapt the block cross-validation method based on
Burman et al. (1994) and Racine (2000) to address the issue. The idea is to break
linkages between training and validation sets by putting blocks of sample observed at
consecutive time periods into the same validation set and leaving time gaps between
training and validation sets.
For a K fold cross-validation, let (Bk,train , Bk,test ) be the kth set of training and
validation set, k = 1, 2, ..., K. Let T = {1, 2, ...T } be the set of time in the sample.
T is divided into K blocks of consecutive time blocks:
Tk = {t| (k − 1) bT /Kc + 1 ≤ t ≤ k bT /Kc} for 1 ≤ k < K,
(8)
TK = {t| (K − 1) bT /Kc + 1 ≤ t ≤ T } .
(9)
Bk,test is defined as
Bk,test = {(i, t) |i = 1, ..., N ; t ∈ Tk } .
(10)
Bk,train = {(i, t) |i = 1, ..., N ; t < min Tk − h or t > max Tk + 2h} ,
(11)
Bk,train is defined as
where we leave a gap of h before the oldest observation in Bk,test to account for the
fact that Cit+1,t+h is not known until t+h; and a gap of 2h after the latest observation
in Bk,test to further decrease the time-series dependence between the training and the
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validation set.
Our proposed cross-validation method is used for the selection for model weights
and hyper-parameters of machine-learning models. We focus on a forecast horizon of 4
quarters. The hyper-parameters involved in each model is selected to maximize crossvalidation AUROC, using data up to 2005Q1. After selection of hyper-parameters,
the model weights are estimated with formula adapted from Eq. (7):
∗
w = arg max
w
5
X
(
X
k=1 (i,t)∈Bk,test
log
M
X
h
(k)
wm Cit+1,t+h fˆm
(xit ) + (1 − Cit+1,t+h ) 1 −
(k)
fˆm
(xit )
m=1
(12)
where we use a 5 fold cross-validation on predictors before 2004Q1, and fˆm is
model m estimated with data in Bk,train . The combined model is the sum of 76% of
XGBoost, 5% of Logit regression and 19% of LDA. The SVM and Random Forest have
zero weights. We kept the hyper-parameters and model weights fixed after selecting
them based on predictors before 2004Q1.We discuss how we estimate and evaluate
the model in the next subsection.
(k)
4.3
Model Performance
We adopt two approaches to simulate the model’s performance. The first is “backtesting”: we make predictions with the data available in each time period, and recursively re-estimate the model as new data arrives. The out-of-sample approach
addresses the question about how the model would perform, if it were to be deployed
in the past. A drawback of the out-of-sample approach is that it fails to account for
the fact that the model estimation error decreasing with the sample size, especially
for flexible machine learning models. To evaluate the expected performance of the
model estimated from the full sample, we use the h-block cross-validation such that
the training data covers most of the full sample. We measure the model performance
with log-likelihood and the Area Under the Receiver Operating Characteristic4 Curve
(AUROC).
The out-of-sample exercise starts in 2005Q1. To avoid any forward-looking bias,
we make sure the training data only uses observations available before the testing
4
An receiver operating characteristic curve is a curve showing false positive rates and true positive
rates of a classification model at all classification thresholds. AUC higher than 0.5 indicates the
model is more informative than white noise.
14
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)
i
,
data. Given the definition of Cit+1,t+h , it means the predictors in the training data
are at least 4 quarters behind the corresponding testing set, and the first trainingset uses the predictors before 2004Q1. Each model is re-estimated in Q1 of each
year. Missing predictors are imputed using sample median, when estimating the
model and making forecasts5 . We restrict to observations with no more than 10
missing predictors, such that imputations will not significantly bias model estimates
and predictions. Forecasts are generated conditional on predictors in each quarter of
the year, using the model estimated at Q1 of the year.
The top panel of Table 4 shows the out-of-sample AUROC of each sub model and
the combined model. Each row shows the AUROC based on groups of all economies,
the advanced economies and emerging markets. The combined model generates an
out-of-sample AUROC of 0.67 which is highest across all sub models. The AUROC
computed for AEs and EMs yields similar results, suggesting the combined model is
robust across different groups. The bottom panel of Table 4 shows the out-of-sample
log-likelihood of each sub model and the combined model. The combined model has
the highest likelihood, which validates the Geweke and Amisano (2011)’s assumption
that none of the sub-models is the true data-generating process. By combining sub
models, we ends up with a better model.
To evaluate the expected performance of models estimated from the whole sample,
we compute AUROC and log-likelihood using a 10-fold cross-validation on the whole
sample. The result presented in Table 5 is qualitatively similar to Table 4. The
combined model yields the highest AUROC and log-likelihood relative the sub-models.
The cross-validation AUROC of the combined model is 0.71 which is higher than the
out-of-sample AUROC. The improvement may be attributed to reduced estimation
errors, as larger sample is used to estimate models.
We further check the robustness of the model by looking at the AUROC computed
with forecasts in different time blocks. Figure 7 plots the AUROC of models in
time blocks: 1995-1999, 2000-2004, 2005-2009, 2010-2014 and 2015-2020. With the
exception of the period 1995-1999, the combined model has an AUROC above 0.6 in
all time blocks. The under performance in the period 1995-1999 is possibly due to the
many missing predictors in the earlier sample period, which makes reduce AUROC
of four out of five sub models below 0.55.
5
Exceptions are XGBoost and LDA: the XGBoost package handles missing data internally, while
LDA generates probability conditional on the predictors available.
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4.4
Interpreting Model Predictions with Shapley Values
One caveat and noteworthy cost of flexible machine learning models is the loss of
interpretability relative to linear models. Interpretability is important, because the
model output should, by no means, be taken as the conclusion and applied to all
circumstances in the future. Our model is simply a statistical extrapolation of past
corporate distress events with a set of predictors. Any future corporate sector distress
may have a different nature from past ones, and policy makers may need a broader set
of predictors. By interpreting how the model arrives at its prediction, policy makers
can evaluate the model output and use discretion.
In this section, we use Shapley values to attribute the output of the model to each
predictor. The Shapley values use classical equations from cooperative game theory
to compute explanations of model predictions (Shapley, 1953). It is widely used in
model explanation because of the additive feature that the sum of each predictor’s
Shapley value plus a constant is the model prediction. We use the SHAP Python
package based on the algorithm in Lundberg and Lee (2017) to compute Shapley
values.
The top-five contributors are the Fed Funds shadow rate, 12-month default probability, policy rate, dollar annual appreciation and market index return of the past
year, as shown in the left panel of Figure 8 which presents the mean absolute Shapley values of the top 20 contributors. Among these, the dividend yield, change in
cash-to-asset ratio, capital expenditure to asset ratio, change in return on assets, and
interest coverage ratio contribute negatively to the crisis probability. In other words,
when these values are negative, they contribute positively to the probability of corporate distress. The remaining predictor variables increase the corporate distress risk
as their values increase.
Individual Shapley values of predictors are consistent with our priors. The right
panel of Figure 8 plots the distribution of Shapley values. Each dot represents a Shapley value from one observation. The color represents the level of the corresponding
predictors. The dots are jittered to reflect the distribution of Shapley values. Hence,
a distribution of Shapley values with red dots on the right and blue dots on the left
suggests higher predictor values have positive impact on the outcome. Tight financial
conditions increase the risk of corporate distress. The Fed Funds shadow rate proxies
for global financial conditions and global financial cycle a la Rey (2015) and comes out
as the most powerful predictor variable in our model.The policy rate variable proxies
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for local financial conditions and their tightening when increasing. Our results also
show that the capital expenditure and its change among the top predictors implying that when firms’ capital expenditure is high and increasing rapidly, it increase
the likelihood of corporate distress. Additionally, over-valued stock prices can be a
harbinger of subsequent drastic corrections and corporate distress as reflected by the
distributions of previous market index growth, the price-earnings ratio, market-tobook value and dividend yield. Traditional measures of balance-sheet vulnerability
have the right sign in predicting corporate distress: high net debt to asset ratio, high
capital expenditure to asset ratio, low cash to asset ratio and low interest coverage
ratio increase risks of corporate distress.
It is also informative to examine how variables in each category contribute to
the predictions, because many individual variables each with a small contribution
can have large combined effects. We divide the predictors into four classes: firmlevel balance-sheet variables, market valuation, domestic macroeconomic variables
and global financial conditions as listed in Table 2. The global financial condition
category includes the USD appreciation and Fed Funds shadow rate. The Shapley
value of each category is the summation of Shapley values of individual predictors
in the category. Figure 9 presents the mean absolute values of predictors from each
category. The top two categories are the global financial condition variables and
balance-sheet variables which have similar contributions. These imply that firms’
financial health and indebtedness have the highest signaling value for a looming systemic corporate distress. (Unexpected) Changes in global financial conditions, i.e.,
interest rates and other push factors could trigger systemic bankruptcies in the corporate sector considering firms’ exposure to international economic developments.
The third and fourth are valuation variables and domestic macroeconomic variables
whose respective contributions are about half of the top two. The deviation from
the fundamentals and asset price bubbles also collectively signal and precede corporate distress albeit to a lesser degree. Lastly, domestic macro variables such as
inflation, GDP slowdowns, domestic financial cycles and banking sector exposure to
firms are included in the fourth group of variables, indicating their relatively lower
power collectively as a group.
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4.4.1
An Application: Corporate Distress Risk Index for Emerging Markets
We use the average model results for emerging markets to illustrate an application
and how our model works in terms of measuring corporate distress probability over
time. The results are forward looking with a four-quarter horizon, i.e., the risk index
at end-2021 shows the probability of corporate distress in 2022. Starting in 2005,
the evolution of the risk index, as illustrated in the solid blue line in Figure 10,
captures the key past corporate crises in EMs, namely, the 2007-08 Global Financial
Crisis and 2020 Covid shock.
The contribution of each of the four variable categories can also be seen in Figure 10. The gap between the total risk index and the aggregate Shapley values of
variables is due to the constant in the model that is the same for all economies
in each quarter. The breakdown of the risk index shows that ahead of the GFC,
the risk index spiked due loose global financial conditions and market valuation
anomalies. At the onset of the GFC, which stemmed from AEs, EM corporates suffered from increasing balance sheet vulnerabilities and higher default probabilities.
The most recent surge in the risk index 2020Q1 shows increasing corporate distress
on the back of corporates’ balance sheet vulnerabilities and tight global financial
conditions. the risk subsides in the following quarters with loose global financial
conditions. In 2022Q2, we observe an increase in systemic corporate distress probability with the tightening of global financial conditions and the presence of balance
sheet vulnerabilities.
Figure 10: Shapley Value Decomposition of Average EM Indices
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5
Macroeconomic Implications of Systemic Corporate Distress: Initial Findings
As the final part of our empirical analysis, we study the macroeconomic implications
of systemic corporate distress with the aim to shed light on our future research. We
examine how key macroeconomic variables behave around corporate distress. To
this end, we focus on GDP growth, bank credit to nonfinancial corporations (NFCs),
foreign direct investment (FDI) and exchange rates and compare around the corporate
distress episodes identified in our model. Utilizing a panel of advanced economies and
emerging markets data, we report the preliminary findings on the real effect of high
corporate distress in different economy groups.
To see the general effects of high corporate distress, we regress the posterior probability of high stress regimes on annualized GDP growth and credit growth with
economy-level fixed effects.
Yit = cit + βunconditional Probit + εit .
(13)
The model is at quarterly frequency. The first row of Table 4 shows the estimates:
on average, GDP growth during high corporate distress periods is lower by 3.0%
relative to low stress periods. The unconditional effect on credit growth is -2.1%
and marginally significant at the 10% level. The second and third rows illustrate the
effects on AEs and EMs respectively by estimating the model with fixed effects:
Yit = cit + [βAE IAE (i) + βEM (1 − IAE (i))] Probit + εit ,
(14)
where IAE (i) is 1 for AEs and 0 for EMs. The estimates shows high corporate distress regime significantly reduces GDP growth by 2.4% and 3.9% for AEs and EMs
respectively. In terms of credit growth, high corporate distress regimes don’t have
significant effect on AEs, but the effect is strong on EMs: credit growth is reduced
by 6.5%. Hence, corporate distress has significant negative effect on GDP growth of
both AEs and EMs. But the effect on credit is limited to EMs.
In comparison to financial/banking crises, the evidence on the macroeconomic
consequences of corporate crises is scarce in the literature. Empirically, financial
crises induce more severe disruptions to economic growth than typical recessions as
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demonstrated by Schularick and Taylor (2012) and Claessens et al. (2012). Related to
the corporate sector distress, Giesecke et al. (2014) study the macroeconomic effect
of corporate defaults and find that corporate default crises have far fewer impacts
than banking crises. Considering that our high corporate distress periods overlap
with many banking crises (Figure 4), our results might be biased. To overcome this,
we estimate the conditional growth of GDP and credit during only high corporate
distress but non-banking-crisis periods, and also estimate the effect of banking crises
jointly using the following model:
Yit = cit + βN onf inancial DummyN onf inancial,it + βF inancial DummyF inancial,it + εit , (15)
where DummyN onf inancial,it is an indicator function for high-corporate-stress periods,
but set to 0 when the is a concurrent banking crisis. The fourth and fifth rows of
Table 6 present the estimates. Both our results and Giesecke et al. (2014) suggest
that corporate distress has a milder effect on GDP growth than banking crises. We
find that GDP growth decreases by 1.6% during corporate distress versus by 3.8%
during banking crises. This can be attributed to the credit channel. During banking
crises, credit growth decreases by around 5.6% while the effect of corporate distress
on credit is insignificant. Contrary to Giesecke et al. (2014)’s finding that corporate
defaults do not affect growth in the US, we do find that corporate sector distress has a
significant negative impact on growth. The difference can be explained by the crosseconomy nature of our analysis, where the results come from a panel of 55 economies.
It can also be attributed to our forward-looking measure: we use default probabilities
derived from Merton’s distance to default, firm-level solvency and liquidity measures
as a proxy for corporate sector stress, which is more forward-looking than the actual
default data.
We further examine the impact of high PDs during financial crises and high PDs
without financial crises (i.e. pure corporate distress) by conducting the above analysis for AEs and EMs blocks separately. Rows 6-10 in Table 6 present the results.
Consistent with the previous estimates, pure corporate distress has a milder impact
than banking crises in terms of GDP growth: high PD regimes reduce GDP growth
by 1.6% for AEs and 2.2% for EMs. The difference in impact is more prominent
for credit growth during pure corporate distress periods: high PD regimes increase
credit growth by 0.8% for AEs, though the impact is not statistically significant.
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However, high PD regimes reduce credit by 3.8% for EMs. Hence, the credit channel
is significant for EMs even without concurrent bank crises.
One possible explanation for the sharp decrease in credit growth in EMs could
the decrease in capital flows during corporate distress periods. While the direction
of causality is not clear, capital inflows to EMs increase the supply of credit in the
economy leading to credit booms. However, if either due to corporate sector distress
or due to exogenous global factors, any sudden stops in capital inflows would have
a significant impact on credit. Otherwise, corporate distress might increase international investors’ risk aversion. To shed some light on this, we re-estimate Eq. (13),
(14) and (15) with exchange rate growth and foreign direct investment growth as
dependent variables. Table 7 shows the results. The second and third rows in Table
7 show that high corporate distress regimes are linked to currency depreciation in
EMs of about 8.8%, and decrease in FDI by 20%, while the impact on AE exchange
rates and foreign direct investment is insignificant. Rows 6 and 8 show the impact of
high PDs during corporate distress periods on AEs and EMs, respectively. Without
concurrent financial crises, high corporate sector distress is linked to drops in EM
exchange rates and foreign direct investment by 6.2% and 11.5%, respectively, while
the impact on AEs is insignificant.
While contemporaneous results indicate a lower GDP growth during corporate
crises in AEs and EMs, it is lower than those reported during banking crises. We also
find evidence on a significant decrease in credit, FDI and exchange rates (depreciation)
during corporate crises in EMs. These findings are robust to the impact of concurrent
banking crises. However, these results do not clearly identify a causality or Granger
causality that corporate distress is likely to follow or coincide with other types of
macroeconomic crises in economies.
6
Conclusion
In this paper, we study corporate crises and distress by proposing a new cross-economy
measure, constructing an early warning model, and analyzing the macroeconomic
consequences. Our early-warning system of corporate sector distress combines several
state-of-the-art machine learning methods with robust out-of-sample performance.
Our findings illustrate the importance of corporate balance sheet variables and global
financial conditions in predicting corporate crises. Furthermore, the results show the
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significant impact of corporate distress on GDP and credit growth.
Our results have important policy implications for macroprudential and monetary policies.Our analysis shows that corporate distress has a milder impact than
financial crises and its effect on GDP and credit growth is larger in EMs than AEs.
From a macrofinancial point of view, the spillover and spillback channels are significant warranting preemptive policies to mitigate the macroeconomic cost of systemic
bankruptcies and corporate crises. Surveillance of corporate sector stability and its
linkages to the rest of the economy could provide early enough signals of accumulating risks highlighting the importance of integrated policy frameworks. Understanding
the risks created in different segments of an economy by monetary, fiscal and financial policies could help policymakers avoid systemic crises and their long lasting cost.
This paper underscores the importance of close and timely monitoring of corporate
vulnerabilities and implemetation of contingency plans to address these risks in case
of materialization.
There are a number of caveats in our work. First, our analysis is limited to
publicly listed firms due to data availability. This unfortunately forces us to leave
SMEs and private firms out, although in some economies these players constitute a
key part of the economy. Secondly, we focus only on advanced and emerging/frontier
economies leaving out low-income economies and fragile states. Since our analysis
requires availability of high-frequency longitudinal data, we are limited to economies
with good data availability. As more data becomes available, we plan to extend our
model and work beyond the current economy coverage.
Using our new dataset and measure of corporate distress, our plans for future
research include a more thorough analysis of its macroeconomic impact, linking policy effectiveness around corporate crises and the role of macroprudential policy in
avoiding systemic financial crises. Another research avenue is looking into sectoral
differences as well as the public vs private ownership. The macroeconomic-impact
results we document in this paper for EMs warrants a thorough analysis of the underlying reasons for differences between AEs and EMs.
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Table 1: Summary Statistics for the Economy-level PD Indices
Starting period
N observations
N firms covered
1995Q3
1992Q1
1992Q2
2011Q4
1991Q2
1995Q2
2006Q1
1994Q1
1995Q2
1995Q2
2006Q2
2006Q2
1999Q2
1996Q2
1991Q2
2007Q1
1992Q3
1990Q2
1990Q4
1993Q2
1992Q1
1996Q3
2000Q4
1994Q2
1992Q4
1993Q1
1995Q2
1990Q1
2011Q3
1995Q3
2001Q3
2009Q3
1993Q2
2001Q1
2007Q1
2005Q2
2004Q4
1991Q3
2011Q1
1995Q2
2003Q4
1990Q2
1993Q3
2004Q2
1991Q3
2011Q1
2004Q2
1997Q2
1992Q4
1995Q4
1994Q2
2012Q4
1999Q2
1999Q2
2001Q2
2009Q1
1992Q1
2004Q2
1993Q4
1992Q1
2006Q3
1991Q3
1990Q2
1992Q2
1994Q1
2004Q1
2002Q4
2007Q1
2007Q2
1990Q1
1990Q4
2007Q1
105
119
118
40
122
106
63
111
106
106
34
62
90
39
122
59
117
126
124
114
119
100
18
110
116
115
103
127
37
105
81
49
114
83
8
66
64
121
36
106
72
126
113
70
121
43
70
98
116
104
110
36
85
88
82
43
119
55
112
119
61
121
126
118
111
71
76
39
58
127
124
59
56
1,044
62
167
83
203
49
708
104
1,936
21
97
56
48
104
134
108
470
501
202
636
27
31
2,006
238
53
311
179
32
3,215
83
33
1,325
52
23
26
26
617
22
79
46
115
71
83
129
46
155
43
116
258
44
22
57
130
87
64
335
30
251
106
152
332
156
572
377
33
259
37
39
1,036
3,672
448
Average Standard deviation
25 quartile
Median
75 quartile
0.27
0.08
0.09
0.08
0.08
0.35
0.27
0.15
0.08
0.33
0.05
0.12
0.19
0.11
0.09
0.32
0.08
0.09
0.09
0.21
0.08
0.08
0.22
0.55
0.27
0.06
0.12
0.10
0.22
0.06
0.10
0.11
0.15
0.12
0.07
0.07
0.11
0.11
0.20
0.09
0.05
0.08
0.02
0.23
0.12
0.05
0.16
0.06
0.12
0.18
0.09
0.04
0.11
0.16
0.06
0.18
0.05
0.06
0.13
0.09
0.15
0.06
0.05
0.03
0.13
0.11
0.22
0.38
0.11
0.08
0.11
0.17
0.50
0.10
0.16
0.11
0.12
0.52
0.46
0.25
0.11
0.56
0.07
0.16
0.32
0.16
0.13
0.43
0.14
0.14
0.17
0.37
0.12
0.12
0.28
0.86
0.36
0.10
0.20
0.18
0.33
0.11
0.13
0.14
0.32
0.16
0.08
0.09
0.15
0.16
0.30
0.18
0.07
0.13
0.03
0.32
0.17
0.07
0.22
0.11
0.20
0.24
0.13
0.05
0.16
0.25
0.09
0.20
0.08
0.10
0.19
0.14
0.22
0.09
0.07
0.05
0.19
0.14
0.29
0.57
0.15
0.13
0.19
0.23
0.76
0.16
0.29
0.17
0.24
0.82
0.59
0.50
0.27
2.06
0.20
0.22
0.56
0.33
0.20
0.61
0.25
0.26
0.29
0.58
0.16
0.20
0.42
1.15
0.69
0.19
0.28
0.69
0.41
0.21
0.18
0.18
0.70
0.23
0.10
0.20
0.25
0.29
0.60
0.36
0.09
0.21
0.06
0.45
0.24
0.41
0.33
0.50
0.36
0.32
0.40
0.06
0.36
0.34
0.16
0.54
0.14
0.14
0.27
0.28
0.29
0.18
0.12
0.12
0.37
0.18
0.45
0.67
0.21
0.20
0.68
0.29
Economy
Argentina
Australia
Austria
Bangladesh
Belgium
Brazil
Bulgaria
Canada
Chile
China
Colombia
Croatia
Cyprus
Czech Republic
Denmark
Egypt
Finland
France
Germany
Greece
Hong Kong SAR
Hungary
Iceland
India
Indonesia
Ireland
Israel
Italy
Jamaica
Japan
Jordan
Kenya
Korea
Kuwait
Latvia
Lithuania
Luxembourg
Malaysia
Mauritius
Mexico
Morocco
Netherlands
New Zealand
Nigeria
Norway
Oman
Pakistan
Peru
Philippines
Poland
Portugal
Qatar
Romania
Russia
Saudi Arabia
Serbia
Singapore
Slovenia
South Africa
Spain
Sri Lanka
Sweden
Switzerland
Taiwan Province of China
Thailand
Tunisia
Turkey
Ukraine
United Arab Emirates
United Kingdom
United States
Vietnam
0.62
0.14
0.25
0.13
0.23
0.65
0.48
0.52
0.18
1.13
0.13
0.20
0.57
0.23
0.16
0.46
0.22
0.22
0.23
0.46
0.15
0.21
0.33
0.87
0.73
0.16
0.24
0.66
0.36
0.19
0.14
0.16
0.66
0.20
0.10
0.17
0.23
0.23
0.44
0.25
0.07
0.21
0.06
0.37
0.21
0.21
0.27
0.31
0.40
0.28
0.27
0.05
0.36
0.37
0.16
0.39
0.12
0.13
0.23
0.21
0.25
0.18
0.10
0.10
0.43
0.15
0.37
0.61
0.18
0.17
0.42
0.24
0.53
0.11
0.24
0.06
0.41
0.39
0.28
0.74
0.16
1.00
0.12
0.16
0.87
0.20
0.11
0.22
0.31
0.26
0.23
0.32
0.12
0.28
0.20
0.38
0.86
0.19
0.16
1.04
0.23
0.20
0.07
0.09
1.11
0.15
0.05
0.23
0.24
0.17
0.38
0.21
0.03
0.25
0.06
0.21
0.15
0.22
0.18
0.41
0.54
0.17
0.27
0.02
0.81
0.67
0.20
0.34
0.12
0.12
0.13
0.20
0.13
0.38
0.08
0.12
0.68
0.07
0.23
0.37
0.11
0.14
0.44
0.10
Notes: The third column, labeled ’N observations’, shows the number of quarters when the economy level index is available. The fourth column, labeled ’N firms covered’,
shows the average number of firms each quarter.
26
©International Monetary Fund. Not for Redistribution
Table 2: Predictor Definition and Data Sources
27
Panel A: Balance-sheet Variables and PDs
Lable
Investment Rate
Investment Rate (change)
Net Current Assets to Total Assets
Net Current Assets to Total Asset Ratio (change)
Debt to Asset Ratio
Debt to Asset Ratio Change
Default probability 12 month
Default probability 12 month (change)
Default probability 36 month
Default probability 36 month (change)
Interest Coverage Ratio (moving average)
Interest Coverage Ratio (change)
Net Debt (exl. liquid assets) to Asset Ratio
Net Debt (exl. liquid assets) to Asset Ratio
(change)
ROA
ROA (change)
Short-term investment to liability ratio
Short-term investment to liability ratio (change)
Definition
Median of capital expenditure to lagged capital stock of firms from each economy
Annual changes in investment rates
Median of net current assets to total asset ratio across firms from each economy
Annual changes in net current assets to total asset ratio
Median of debt to asset ratio across firms from each economy
Annual changes in debt to asset ratio from each economy
Capital-weighted averages of 12-month default probability across non-financial firms from each economy
Quarterly changes in default probability 12 month
Equal weighted averages of 36-month default probability across non-financial frims from each economy
Quarterly changes in default probability 36 month
Annual moving averages of median of interest coverage ratio across firms from each economy
Annual changes in median of interest coverage ratio
Median of net debt (exl. liquid assets) to asset ratio
Annual changes in net debt (exl. liquid assets) to asset ratio
Source
Compustat Global
Compustat Global
Compustat Global
Compustat Global
Compustat Global
Compustat Global
NUS Credit Research
NUS Credit Research
NUS Credit Research
NUS Credit Research
Compustat Global
Compustat Global
Compustat Global
Compustat Global
Return on assets computed as EBIT divided by total assets
Annual changes in return of asset
Median of cash and short-term invest to liability ratio
Annual changes in short-term investment to liability ratio
Compustat
Compustat
Compustat
Compustat
Panel B: Macroeconomic Variables
Lable
GDP gap
Inflation
Foreign Reserve gap
Gov Bond Yield 10y
Policy Rate
Credit GDP Ratio
Definition
One-sided GDP gap, computed by HP filter with Lambda = 1,600
YoY% inflation rate
One-sided foreign reserve gap, computed by HP filter with Lambda = 1,600
Gov Bond Yield 10y
Policy Rate
Credit GDP Ratio
Credit GDP Gap
Credit GDP Gap
Quarterly real GDP growth
BOP to corporate sector to GDP ratio
Fed Funds Shadow Rate
Dollar Appreciation
Real GDP growth
BOP other inv. (net) to non-official, non-bank sector-to-GDP ratio
Wu-Xia Shadow Federal Funds Rate
YoY% Dollar Appreciation
Source
World Economic Outlook
World Economic Outlook
International Financial Statistics - IMF Data
Global Financial Data
Global Financial Data
Bank of International Settlement, and IMF staff calculates
Bank of International Settlement, and IMF staff calculates
World Economic Outlook
Bank of International Settlement
Federal Reserve Bank of Atlanta
Information Notice System - IMF Data
Panel C: Stock Price Valuation
Lable
Dividend Yield
Market Index Growth
Price Earning Ratio
Market to Book Value
Volatility of Market Index
Definition
Dividend Yield
YoY% return of market index
Price Earning Ratio
Maket value over book value of market index
Volatility of Market Index
Source
Datastream
Datastream
Datastream
Datastream
Datastream
©International Monetary Fund. Not for Redistribution
Initiative
Initiative
Initiative
Initiative
Global
Global
Global
Global
Table 3:
Model
Posteiors of Key Parameters in the Markov Regime-switching
ρ
δ+1 γ+1
p11
p22
5.9
0.15
5.9
5.63
6.17
0.95
0.00
0.95
0.94
0.96
0.81
0.01
0.81
0.78
0.83
Posteior
Mean
Standard deviation
Median
5% Quantile
95% Quantile
0.91
0.01
0.91
0.90
0.92
3.67
0.85
3.68
2.33
5.09
Table 4: Out-of-sample Model Performance
AUROC
XGBoost
All Economies
Advanced Economy
Emerging Market
0.65
0.68
0.62
Logit
SVM
0.64
0.63
0.65
0.55
0.55
0.54
Random Forest
0.59
0.61
0.57
LDA
0.64
0.63
0.65
Combination
0.67
0.68
0.65
Log-likelihood
XGBoost
All Economies
Advanced Economy
Emerging Market
−1083.42
−583.98
−499.45
Logit
SVM
−1163.00
−666.75
−496.25
−1476.90
−866.67
−610.23
Random Forest
−1146.92
−646.96
−499.96
LDA
−1274.32
−758.36
−515.96
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©International Monetary Fund. Not for Redistribution
Combination
−1071.11
−590.81
−480.31
Table 5: Cross-validation Model Performance
AUROC
XGBoost
All Economies
Advanced Economy
Emerging Market
0.68
0.70
0.66
Logit
SVM
0.66
0.68
0.63
0.56
0.57
0.54
Random Forest
LDA
0.67
0.69
0.63
0.70
0.71
0.67
Combination
0.71
0.72
0.68
Log-likelihood
XGBoost
All Economies
Advanced Economy
Emerging Market
−1550.17
−919.30
−630.86
Logit
SVM
−1572.41
−940.87
−631.54
−2215.94
−1380.72
−835.22
Random Forest
−1539.27
−924.51
−614.76
LDA
−1736.38
−1027.45
−708.94
Combination
−1471.33
−883.95
−587.38
Table 6: Conditional Growth Rates of GDP and Credit to Private Nonfinancial Sector during High Corporate Distress Periods, Relative to Low
Corporate Distress Periods
GDP
Unconditional
AE
EM
Nonfinancial
Financial
AE Nonfinancial
AE Financial
EM Nonfinancial
EM Financial
Credit
∗∗∗
∗
−2.96
(0.43)
−2.06
(1.13)
−2.40∗∗∗
(0.53)
−3.93∗∗∗
(0.66)
0.28
(1.00)
−6.49∗∗∗
(2.06)
−1.82∗∗∗
(0.34)
−4.03∗∗∗
(0.50)
−0.78
(0.82)
−5.62∗∗∗
(1.08)
−1.60∗∗∗
(0.47)
−4.15∗∗∗
(0.69)
−2.23∗∗∗
(0.43)
−3.75∗∗∗
(0.63)
29
©International Monetary Fund. Not for Redistribution
0.84
(0.76)
−3.82∗∗∗
(0.76)
−3.80∗∗
(1.57)
−9.03∗∗∗
(2.58)
Table 7: Conditional Growth Rates of Exchange Rates and Foreign Direct Investment during High Corporate Distress Periods, Relative to Low
Corporate Distress Periods
Foreign Direct Investment
Exchange Rate
Unconditional
AE
EM
Nonfinancial
Financial
AE Nonfinancial
AE Financial
EM Nonfinancial
EM Financial
−3.38∗∗∗
(1.09)
−8.38∗∗∗
(2.75)
−0.53
(0.94)
−8.86∗∗∗
(1.80)
−3.85
(2.84)
−19.87∗∗∗
(4.62)
−2.40∗∗
(0.98)
−2.51∗∗∗
(0.96)
−5.85∗∗
(2.31)
−9.60∗∗∗
(3.68)
−0.25
(0.87)
−0.44
(0.71)
−6.23∗∗∗
(1.83)
−7.80∗∗∗
(2.24)
30
©International Monetary Fund. Not for Redistribution
−2.79
(2.59)
−4.30∗∗
(2.04)
−11.52∗∗∗
(3.87)
−41.69∗∗∗
(7.58)
Figure 1: Average PD Indices and Number of Economies in Corporate Distress across Advanced Economies and Emerging Markets
(a) Average PD Indices
(b) Number of Economies in Corporate Distress
31
©International Monetary Fund. Not for Redistribution
Figure 2: Probability of Default Indices and Posterior Probability
(a) US
(b) Japan
(c) China
(d) Brazil
32
©International Monetary Fund. Not for Redistribution
Figure 3: Posterior Probability of the High Corporate Distress Regime
(a) Posterior
(b) Crises Periods
33
©International Monetary Fund. Not for Redistribution
Figure 4: Corporate Distress Periods vs. Banking Crises Periods
34
©International Monetary Fund. Not for Redistribution
Figure 5: Corporate Distress Periods vs. Currency and Sovereign Debt
Crises Periods
35
©International Monetary Fund. Not for Redistribution
Figure 6: Predictor Availability
Figure 7: Cross-validation AUROC
36
©International Monetary Fund. Not for Redistribution
Figure 8: Summary of Shapley Values
(a) Mean absolute Shapley values
(b) Shapley values distribution
37
©International Monetary Fund. Not for Redistribution
Figure 9: Summary of Shapley Values of Predictors from Different Categories
38
©International Monetary Fund. Not for Redistribution
A
MCMC Algorithm to Identify Corporate Distress
Commonly used conjugate priors are adopted to increase the speed of estimation.
We assume p11 and p22 have independent priors Beta(1,1). We assume δ has flat
Gaussian prior, δ ∼ N (0, ∞) with positive constraints. For identification purposes,
we assume ρ has flat Gaussian prior, ρ ∼ N (0, ∞), with constraints ρ ∈ (0, 1) to
ensure stationarity. The inverse of variance ratio of high-PD regime over low-PD
regime, 1/(1 + γ)2 has prior of Gamma(2,2). Conditional mean of PDs in low-risk
2
regime, µiL is assumed to have flat Gaussian prior, µiL ∼ N (0, ∞), and 1/σiL
has
prior of Gamma(2,2).
Before elaborating on the MCMC algorithm, we define some notations. Let S̃it
denotes vector of states S̃iT = [Si1 , Si2 , ..., SiT ] of economy i, and let ỹiT denote the
vector of observations, ỹiT = [P Di1 , P Di2 , ..., P DiT ]. MCMC sampling are implemented using the steps below:
2
(i ∈ {1, 2, ..., N }) are proposed.
1. Initial values of p11 , p22 , δ, γ, ρ, µiL , σiL
2. For each i = 1, 2, ..., N , sample vector of states S̃iT = [Si1 , Si2 , ..., SiT ] is sam
2
, ỹiT using multi-move Gibbs-sampling
pled from f S̃iT |p11 , p22 , δ, γ, ρ, µiL , σiL
as proposed in Carter and Kohn (1994).
2
, ỹiT .
3. For each i = 1, 2, ..., N , sample µiL from f µiL |S̃iT , p11 , p22 , δ, γ, ρ, σiL
2
2
4. For each i = 1, 2, ..., N , sample σiL
from f σiL
|S̃iT , p11 , p22 , δ, γ, ρ, µiL , ỹiT .
5. Sample p11 , p22 from f p11 , p22 |S̃1T , S̃2T , ..., S̃N T .
2
6. Sample ρ from f ρ|S̃iT , p11 , p22 , δ, γ, µiL , σiL
, ỹiT , for all i ∈ {1, 2, ..., N } .
2
7. Sample δ from f δ|S̃iT , p11 , p22 , ρ, γ, µiL , σiL
, ỹiT , for all i ∈ {1, 2, ..., N } .
2
8. Sample γ from f γ|S̃iT , p11 , p22 , ρ, δ, µiL , σiL
, ỹiT , for all i ∈ {1, 2, ..., N } .
Finally, we repeat steps 2-8 until the Markov chain is properly mixed, and we accumulate enough samples to represent the posterior distribution.
39
©International Monetary Fund. Not for Redistribution
B
Constructing
Predictors
from
Compustat
Global
We use quarterly data on listed non-financial corporations for 55 economies from
S&P Compustat North America and Compustat Global. We exclude financial firms,
namely banks, diversified financial, and insurance firms from our analysis. Our final
sample comprises an unbalanced panel of 56,758 non-financial firms over 1995q12021q3. We first compute the balance-sheet ratio of individual firms, and then take
cross-sectional median at each quarter. Below is the definition of the financial ratios:
• Investment Rate = Capital Expenditure / Previous-Quarter Value of Property,
Plant and Equipment
• Net Current Asset to Asset Ratio = (Current Asset-Current Liabilities) / Asset
• Debt to Asset Ratio = (Debt in Current Liabilities+Long-term Debt) / Asset
• Interest Coverage Ratio = Earning before interest and taxes / Interest expense
• Net Debt to Asset Ratio = (Debt in Current Liabilities+Long-term Debt(Current Liability-Debt in Current Liabilities)) / Asset
• ROA = ( 0.625 · Earning before interest and taxes) / (Asset + Lagged Asset/2)
• Short-term Investment to Liability Ratio = Cash and Equivalent / Liabilities
We make the following adjustments:
• Drop observations for missing assets and liabilities.
• Drop observations when acquisitions are larger than 5% of total assets.
• Winsorize variables at the 1%/99% percentiles at the economy level.
• To ensure representativeness, we drop economies with fewer than 5 firms at each
point in time.
• To ensure further representativeness, we only compute medians for each indicator at each point in time and for each economy when the coverage is at least
30% of all firms reporting data.
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©International Monetary Fund. Not for Redistribution
• We use annual moving average of quarterly interest coverage ratio, investment
rate and ROA to filter out the seasonality in the quarterly earnings and investments.
C
Machine Learning Models and Hyperparameter
Selection
In this section, we elaborate on machine-learning models that we used.
C.1
Logistic Regression with Regularization
Logistic regression belongs to the class of generalized linear model. The outcome
variable yi takes values 0 and 1. Let Xi be a column vector of predictors. The
probability that yi = 1 takes the form
Prob (yi = 1) =
exp (Xi0 β)
,
1 + exp (Xi0 β)
where β is a column vector. The parameter β is estimated by minimizing the summation of the log-likelihood function and a regularization function:
β̂ = arg min −
β
N
1 X
[yi ln (Prob(yi = 1)) + (1 − yi ) ln (1 − Prob(yi = 1))] + C kβk2 .
N i=1
Parameter C is a hyperparameter that determines the amount of regularization: the
larger the value of C, the greater the amount of shrinkage and thus the coefficients
are less prone to overfit the sample.
C.2
Random Forest
Random forest is an algorithm that combines the predictions from many individual
randomized decision trees. The averaging method diversify the forecast errors of
individual predictors, and address the issue of overfitting. We first introduce decision
trees.
A decision tree is a classification algorithm that recursively makes decisions based
on one predictor and one threshold at each node: Once determined the predictor is
41
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above or below the threshold, we proceed to the sub tree and repeat the process, until
there is no sub trees, or a leaf has been reached. The resulting predicted probability of
each class is the proportion of each sample class in the leaf. The binary classification
is estimated recursively: At each node, variable j and split point s are selected to split
the sample into two groups, L(j, s) and S(j, s) with NL and NR samples respectively.
We seek the splitting variable j and split point s that solve
h
min NL ȳL(j,s) 1 − ȳL(j,s) + NR ȳR(j,s) 1 − ȳR(j,s)
j,s
i
.
We continue to split each nodes until the height of the tree reaches a specified maximum length.
The random forest algorithm averages predictions from randomized decision trees.
Each tree in the ensemble is built from a sample drawn with replacement. Furthermore, when splitting each node during the construction of a tree, the best split is
selected from a random subset of predictors, with specified number of predictors in
the subset. The hyperparameters to be set with cross-validation are the maximum
height of individual trees, the size of subset of predictors from which the best split is
selected, and the number of individual trees to combine. To reduce computation burden, we left the other hyperparameters to default values in the Scikit-learn (Pedregosa
et al., 2011) RanfomForestClassifier function.
C.3
Support Vector Machine
Support vector machine (SVM) is a classification algorithm that produces nonlinear
boundary in the feature space. SVM first implement nonlinear function to map the
feature space into a new feature space. Then, it separates the new feature space with
a hyperplane. We start by introducing SVM when the boundary is linear.
Define a hyperplane by
{x : f (x) = x0 β + β0 = 0} .
SVM solves
min
β,β0
N
X
1
kβk2 + C
ξi
2
i=1
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©International Monetary Fund. Not for Redistribution
subject to
ξi ≥ 0, yi (x0i β + β0 ) ≥ 1 − ξi ∀i.
ξi measures how much the sample is within the margin or violate the separation by
hyperplane. The hyperparameter C characterize the cost of misclassification. Given
the solutions β̂0 and β̂1 , the decision function can be written as
h
i
Ĝ (x) = sign x0 β̂ + β̂0 .
The linear boundary can be easily extended to the nonlinear boundary by mapping
x to h(x) where h is a vector function. It turns out the solution involve h(x) through
inner product:
K (x1 , x2 ) = hh(x1 ), h(x2 )i .
Three popular choices for K in the SVM literature are
dth degree polynomial:K (x1 , x2 ) = (γ hx1 , x2 i + κ)d ,
Radial basis:K (x1 , x2 ) = exp −γ kx1 − x2 k2 ,
Neural network:K (x1 , x2 ) = tanh (γ hx1 , x2 i + κ) .
The form of K can be treated as hyperparameters. To reduce the computational burden of tuning hyperparameters, coefficients γ and κ are set as default in Scikit-learn
(Pedregosa et al., 2011) SVC function (γ = 1/number of features, κ = 0). Hence, we
only need to select K and C through cross-validation.
SVC does not yield probability about each class. To get the probability, we fit a
logit model using scores of sample observations. The calibration of logit parameters
is through cross-validation conducted internally in the SVC function.
C.4
Linear Discriminant Analysis
Linear discriminant analysis assume features are generated from distinct multivariate
Gaussian distributions from each class. The predicted probability is the posterior
conditional on the observed feature.
LDA assumes samples of class 0 and 1 are independently generated with probability 1 − p and p respectively. Conditional on the class c, features are generated from
Gaussian distributions N (µc , Σ) , c ∈ {0, 1}. The posterior probability that sample i
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©International Monetary Fund. Not for Redistribution
is from class 1 is
pφ (xi |µ1 , Σ)
,
(1 − p) φ (xi |µ0 , Σ) + pφ (xi |µ1 , Σ)
where φ is the probability density function. Model estimation is straightforward: p is
the sample frequency of class 1; µ0 and µ1 are sample mean of features in each classes.
To reduce estimation error, the covariance matrix Σ is estimated shrinkage method.
The resulting estimate Σ̂s is the weighted average of sample covariance matrix Σ̂ and
an identity matrix multiplied the average of diagonal components inΣ̂.
Σ̂s = (1 − α)Σ̂ +
α
tr(Σ̂)I,
N
where N is the number of features. α is a hyperparameter that is selected by crossvalidation.
One advantage of LDA is that its Bayesian framework allows rigorous treatment
of missing predictors: we can just generate posterior from existing predictors without
resorting to imputations. We customize our own LDA functions.
C.5
Extreme Gradient Boosting Tree
Extreme gradient boosting tree (Chen and Guestrin, 2016) is a from of gradient
boosting tree that combines the outputs of many “weak” classifiers to produce a
powerful “committee”. Hence the fitted value of sample (xi , yi ) is
ŷi =
K
X
fk (xi ),
k=1
where fk (xi ) is a base estimator. The model is trained in an additive manner. Let
(k−1)
ŷi
prediction at the k − 1 th iteration, we seek fk to further decrease the objection
function
N
X
(k−1)
l yi , ŷi
+ fk (xi ) + Ω (fk ) ,
i=1
where l is the loss function and Ω penalized the complexity of the model:
1
Ω (f ) = γT + λ kwk2 ,
2
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©International Monetary Fund. Not for Redistribution
where T is the number of leaves in the tree and w ∈ RT is f ’s predicted value at each
node.
Besides regularization, extreme gradient boosting also adopts shrinkage and sub(k−1)
sampling to reduce overfitting. Rather than adding fk to ŷi
, shrinkage only add
ηfk where 0 < η < 1. Each fk is estimated with a random selected subset of sample
to reduce the correlations across basis classifiers. Computationally, extreme gradient
boosting tree uses approximate algorithm for split finding of individual trees to speed
up the program.
In our exercise, we use an equal average of 50 trees as basis predictor fk to further
reduce overfitting. Extreme boosting involves many hyperparameters. To reduce
computational burden, we set some of them to the number commonly used in the
literature: maximum depth of tress is 3; number of samples per tree is 8 (2-years
of observation); random sample size is 50% of total sample size; λ in regularization
function Ω is 1; scale the gradient of samples of yi = 1 (pre-distress periods) to 5 to
address unbalanced classes. We use cross-validation to find hyperparameters for total
number of iterations K, γ in regularization function Ω and shrinkage parameter η.
Because we scaled up the pre-distress periods class, the resulting output of Xgboost is biased estimate of the probability of yit = 1. In order to combine it with
output from other models, we need the predictions to be comparable across models.
To address this issue, we debiase the probability of Xgboost output by
Probunbiased =
Probbiased
.
5 + Probbiased
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Table A1: Corporate Distress Episodes
Periods of corporate distress
Argentina
Australia
Austria
Belgium
Brazil
Bulgaria
Canada
Chile
China
Colombia
Croatia
Cyprus
Denmark
Egypt
Finland
France
Germany
Greece
Hong Kong SAR
Hungary
Indonesia
Ireland
Israel
Italy
Japan
Jordan
Kenya
Korea
Kuwait
Lithuania
Luxembourg
Malaysia
Mexico
Netherlands
New Zealand
Nigeria
Norway
Oman
Pakistan
Peru
Philippines
Poland
Portugal
Romania
Russia
Saudi Arabia
Serbia
Singapore
Slovenia
South Africa
Spain
Sri Lanka
Sweden
Switzerland
Taiwan Province of China
Thailand
Tunisia
Turkey
Ukraine
United Arab Emirates
United Kingdom
United States
Vietnam
2000Q2-2002Q1,
1997Q4-1998Q1,
1998Q3-1998Q3,
1999Q1-2003Q2,
1998Q2-1999Q1,
2008Q2-2009Q1,
2000Q2-2003Q1,
1997Q4-1999Q3,
2006Q1-2006Q4,
2006Q2-2006Q4,
2017Q2-2018Q4
2000Q1-2002Q1,
2000Q4-2002Q3,
2008Q3-2008Q4,
1995Q1-1995Q2,
2000Q2-2003Q2
1995Q1-1995Q1,
1995Q1-1996Q2,
2020Q1
1997Q4-1999Q1,
1998Q3-1998Q4,
1997Q3-2003Q2,
1997Q4-1998Q3,
1995Q1-1996Q2,
1997Q1-1997Q4,
1996Q3-1999Q1,
2008Q4-2008Q4,
2018Q2-2020Q2
1996Q4-2001Q1
2006Q2-2006Q2,
2008Q2-2009Q3
2008Q3-2009Q2,
1997Q3-2000Q4,
1995Q3-2003Q2,
2000Q1-2003Q2,
1997Q4-1998Q4,
2004Q2-2004Q3,
2001Q3-2002Q4,
2018Q2-2020Q3
2008Q2-2009Q3,
1997Q2-1998Q3,
1997Q3-1999Q2,
1998Q3-1998Q3,
1995Q1-1996Q4,
2008Q1-2009Q2,
2008Q3-2009Q1,
2005Q1-2007Q3,
2009Q1-2010Q4,
1997Q4-1998Q2,
2008Q1-2008Q4
1997Q4-2002Q1,
1995Q2-1995Q3,
2008Q2-2009Q2,
1998Q3-1998Q3,
2001Q3-2003Q2,
1995Q1-1996Q1,
1997Q2-1999Q3
2020Q1-2020Q2
2006Q2-2006Q2,
2008Q3-2009Q2,
2008Q4-2009Q1,
2000Q2-2003Q1,
2000Q2-2003Q1,
2008Q1-2008Q4,
2006Q4-2008Q3,
2000Q1-2000Q2,
2000Q1-2003Q2,
2007Q3-2009Q1,
2001Q3-2002Q3,
2011Q4-2014Q1
2008Q3-2009Q1
2000Q3-2001Q3,
2008Q1-2009Q1,
2015Q3-2016Q1
2012Q2-2012Q2, 2015Q3-2015Q3
2001Q3-2004Q1, 2008Q3-2009Q3, 2020Q1-2021Q1
2008Q3-2009Q2, 2018Q4-2019Q1, 2020Q1-2020Q2
2020Q1-2020Q1
2015Q4-2016Q1
2002Q1-2003Q3, 2005Q2-2005Q4, 2011Q3-2012Q1, 2020Q1-2022Q1
2011Q3-2011Q3, 2015Q3-2015Q3, 2021Q3-2022Q1
2008Q1-2009Q2, 2014Q4-2015Q3, 2022Q1-2022Q1
2003Q2-2003Q2, 2006Q1-2007Q1, 2008Q3-2009Q2, 2011Q3-2012Q1
2016Q4-2016Q4
1998Q2-1998Q3, 2000Q3-2002Q2, 2008Q2-2008Q4, 2011Q3-2011Q3, 2012Q2-2012Q2
2000Q2-2003Q2
2008Q1-2009Q2, 2010Q1-2010Q2, 2011Q2-2012Q3, 2013Q1-2013Q1, 2013Q3-2016Q1, 2020Q12000Q2-2001Q2,
2008Q4-2009Q2,
2008Q3-2009Q2
2002Q1-2003Q1,
1997Q4-1998Q1,
1998Q4-2004Q2,
2000Q2-2001Q3,
2016Q3-2017Q3
2008Q3-2009Q1, 2011Q2-2011Q2
2010Q1-2012Q2
2005Q1-2005Q2, 2008Q2-2009Q2, 2016Q2-2016Q2
2000Q4-2002Q3, 2003Q1-2003Q1, 2008Q4-2009Q1, 2017Q3-2017Q3
2008Q1-2008Q2
2007Q4-2009Q4
2008Q4-2010Q3
2011Q3-2012Q2,
2008Q2-2009Q2,
2008Q4-2008Q4
2008Q2-2009Q1,
2000Q3-2002Q1,
2006Q1-2006Q1,
2008Q3-2009Q2,
2019Q3-2020Q1
2000Q1-2002Q3,
2000Q1-2003Q2,
2000Q3-2003Q1,
1998Q3-2003Q1,
2010Q2-2010Q2
2022Q1-2022Q1
2008Q4-2009Q4
2011Q2-2012Q1
1999Q2-1999Q3,
2008Q3-2008Q4,
1999Q1-1999Q1,
2020Q1-2020Q1
2000Q4-2003Q2,
2008Q3-2009Q2,
1997Q2-1999Q1,
2008Q1-2009Q2,
2014Q4-2015Q1
2015Q3-2016Q1,
2008Q2-2009Q2,
2008Q4-2009Q1
2011Q4-2012Q3,
2019Q4-2020Q3
2018Q4-2019Q1, 2020Q1-2021Q2
2012Q2-2012Q2
2007Q4-2009Q2, 2011Q3-2011Q3, 2020Q1-2020Q1
2007Q1-2009Q3, 2016Q1-2017Q1
2011Q3-2011Q3, 2014Q3-2015Q1, 2018Q4-2020Q2
2003Q3-2005Q1, 2006Q1-2006Q2
2008Q4-2009Q1
2008Q4-2009Q2, 2011Q3-2012Q2, 2020Q1-2020Q3
2007Q3-2008Q3
2000Q4-2003Q1, 2008Q1-2009Q2
2015Q3-2015Q3, 2018Q2-2018Q2, 2020Q1-2021Q1
2000Q2-2002Q4, 2012Q2-2012Q2
2008Q2-2009Q2, 2011Q3-2012Q1
2011Q3-2011Q3, 2015Q3-2015Q3, 2018Q4-2018Q4
2000Q1-2001Q4, 2008Q2-2009Q1
2018Q2-2021Q3
2020Q1-2020Q2
2018Q4-2020Q4
2016Q3-2017Q1, 2020Q1-2020Q1
46
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