?

Modelling and forecasting value at risk and expected
shortfall for GCC stock markets: do long memory,
structural breaks, asymmetry, and fat-tails matter?
Forthcoming in North American Journal of Economics and Finance
Financially supported by Fawzen Chair of Macroeconomics Forecasting
Chaker Aloui
College of Business Administration, King Saud University, KSA
Ben Hamida Hela
College of Economics and Administrative Sciences, Al Imam Muhammad
Ibn Saud Islamic University , KSA
Modelling and forecasting value at risk and expected
shortfall for GCC stock markets: do long memory,
structural breaks, asymmetry, and fat-tails matter?
Contents
o
o
o
o
o
o
o
Introduction and research motivations
Main research question
Econometric framework
Data and preliminary analysis
Empirical results
Some risk management implications
Concluding remarks
Introduction and research motivations
GCC stock markets: some stylized facts
Volatility clustering, asymmetry, structural breaks and long memory
1.0
100
ACF-sqared return (QATAR)
squared return (Qatar)
75
0.5
50
25
0
50
100
10
0.75
2004
Density
logarithmic return (Qatar)
2006
2008
2010
2012
2014
RQATAR
0.50
0
0.25
2004
2006
Distribution
10
2008
2010
2012
2014
10
-10
QQ plot
0
5
10
RQATAR ´ normal
RQATAR
0
-5
0
-10
-10
-5
0
5
10
-4
-2
0
2
4
Main objectives and research question
1.
Researching the relevance of LM, structural breaks, asymmetry,
and fat-tails in modeling and forecasting the volatility of GCC
stock markets;
2.
Assessing the predictive ability of LM GARCH-class models under
various return innovations’ distributions (normal, Student-t, and
skewed student-t)
3.
Analyzing the VaR and ES performance for short and long trading
positions.
4.
We connect the VaR analysis to Basel II Capital Accord
requirements
Do LM, structural changes, asymmetry, and heavy tails matter
when quantifying risk using the VaR and ES tools? What are the
main financial implications in terms of risk management?
Econometric framework (1)
Long memory GARCH-class models
o
ARFIMA model (mean process)
o
FIGARCH model (variance process)
o
FIAPARCH model (variance) process
Densities
o
Student t distribtion
o
Skewed Student-t distribution
Econometric framework (2)
Value-at-risk and expected shortfall
o The one-day-ahead VaR:
o The expected shortfall:
Statistical accuracy of model-based VaR’s estimations
We employ two alternative tests,
o Kupiec (1995) test and
o Dynamic Quantile test (DQT) suggested by Engle and Manganelli (2002).
Data and preliminary analysis
 Markets: Kingdom of Saudi Arabia (SASEIDX), Dubai (DFMGI Index)
and Abu Dhabi (ADSMI Index), Oman (MSM30), Bahrain (BHSEASI),
Kuwait (KWSEIDX) and Qatar (DSM).
Source and sample period: Bloomberg daily stock indexes (January, 3nd
2003 to January 22nd, 2013). 2,620 observations
The sample periods are varying across GCC markets and indexes are
expressed in local currencies.
We should note that the last 1,000 observations are reserved to the
out-of-sample forecasts.
Long memory vs. structural breaks
Empirical results
o Long memory
We implement three alternative long-range memory tests: Lo’s (1991) test, the logperiodogram regression (GPH) of Geweke and Porter-Hudak (1983) and the GSP
Robinson (1995) test.
o Structural breaks
We check whether the occurrence of LM is spurious and caused by some structural
breaks.
 We refer to Shimotsu (2006)’s to test the null hypothesis of LM against structural
We confirm the existence of LM in the squared returns and that conditional
volatility of the GCC countries is not caused by the occurrence of structural
breaks. The LM fact is not spurious for all the GCC stock markets.
Results of Inclan and Tiao (1994)’s structural break test
GCC stock
market
Saudi Arabia
Kuwait
Oman
Qatar
Dubai
Abu Dhabi
Bahrain
Number of breaks Break dates
4
3
3
2
3
4
2
09/16/2003 - 04/18/2004 – 06/04/2006 – 09/18/2009
06/13/2003 - 03/09/2005 - 09/18/2009
05/13/2005 - 01/03/2008 - 09/20/2009
09/19/2008 - 01/02/2011
02/08/2005 – 08/16/2007 – 18/09/2008
05/03/2005- 02/08/2005 – 08/16/2007 – 18/09/2008 09/18/2008 – 01/21/2011
 Saudi Arabia and Abu Dhabi stock markets exhibit four structural breaks in their
unconditional variance behavior. Kuwait, Oman and Dubai display at least three
structural breaks.
 2008-2009 global financial crisis is a common break date for all the GCC stock
markets.
 The Arab Spring on January 2011 is identified as a structural change in the
unconditional variance behavior for at least two countries namely Bahrain and Qatar.
Forecasting performance assessment
We employ 1) the mean square error (MSE), 2) the mean absolute prediction
error (MAPE) , 3) the logarithmic loss function (LL), and 4) the Mincer-Zarnowitz
(1969) regression.
Qatar
Saudi Arabia
Kuwait
ARFIMAAR-FIAPARCH
AR-FIAPARCH
FIAPARCH
with skew. St.- t
with St. t
with skew. St.
Oman
ARFIMAFIAPARCH
with St. –t
Dubai & Abu
Dhabi
AR-FIGARCH
with sk. St.-t
Bahrain
AR-FIAPARCH
with sk. St.
Saudi Arabia and Oman , under skewed Student-t innovations distributions, the ARFIMAFIAPARCH model performs better than the other models for both short and long trading
positions.
The selected models under skewed student-t distribution provide the best forecasts for the
VaR and ES.
Some risk management implications:
VaR and Basel II Accord capital requirements
Under the Basel II Capital Accord, the VaR’s predictions of the banks should be
reported to the appropriate authority at the beginning of the day, and are then
compared to actual returns at the end of the day.
These forecasts are used to compute the amount of capital requirements (daily
capital charges) in order to provide a cushion against adverse market situations.
DCC must be set at the higher of the previous day’s
VaR or the average over the business day adjusted by
a scaling factor with reference to three-zone
approach. The scaling factor corresponds to the sum
of 3 and a given multiplicative factor (k) as given in
the table.
The DCC is the penalty that the Basel II imposes on
financial institutions employing models that lead to
a greater number of violations than would be
expected, given a specific confidence level of 99%.
For a daily data, the DCC is given by:
Zone
Nb.
of k
violations
Green
0 to 4
0.00
5
0.40
6
0.50
7
0.65
8
0.75
9
0.85
+10
1.00
Yellow
Red
LM GARCH-class models, VaR forecasts and DCC
under Basel II rules
The number of violations for all the LM-GARCH specifications and all GCC markets is
always less than ten suggesting that these models do not lead to entry in the Basel II
Accord critical zone (i.e. red zone).
In terms of daily average capital charges, the FIAPARCH model under skewed
Student density is the best model followed by the FIGARCH model under Student-t
density as it yields in three cases out of four.
The percentage of violations given by the FIAPARCH-N for three out of seven indexes
is higher than that of the FIAPARCH model under skewed Student and Student
densities indicating that the risk of going into the red zone defined by the Basel II rules
is higher with the FIAPARCH-normal.
The results of the various APARCH specifications are comparable in terms of DCC,
but the APARCH model with skewed Student distribution generates less violations.
Concluding remarks
 LM is particularly strong and plays dominant role in explaining the GCC stock
market returns. The selection tests provide results confirming LM to the detriment
of structural breaks.
 Only two markets, namely Saudi Arabia and Oman exhibit LM in both conditional mean
and variance.
 We uncover the superiority of the FIAPARCH model under skewed Student-t
innovation distribution for the in-sample forecasting exercise.
 For the out-of-sample forecasting, the FIAPARCH model provides the best predictive
ability.
 The VaR seems to work in GCC stock markets and we believe that greater attention
should be paid to LM properties, asymmetry and fat tails when quantifying risk.
Some references
Aloui, C. and Mabrouk, S. 2010.Value-at-risk estimations of energy commodities via
long-memory, asymmetry and fat-tailed GARCH models. Energy Policy 38, 2326-2339.
Conrad, C., Karanasos, M., Zeng, N., 2011. Multivariate fractionally integrated
APARCH modeling of stock market volatility: a multicountry study. Journal of
Empirical Finance 18, 147–159.
Degiannakis, S, C. Floros and P. Dent. 2013. Forecasting value-at-risk and expected
shortfall using fractionally integrated models of conditional volatility: international
evidence. International Review of Financial Analysis 27, 21-33.
Degiannakis, S. 2004. Volatility forecasting: evidence from a fractional integrated
asymmetric power ARCH skewed-t model. Applied Financial Economics 14, 1333–
1342.
Kupiec, P., 1995. Technique for verifying the accuracy of risk measurement models.
Journal of Derivatives 2, 173-184.