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Parametric Value-at-Risk analysis: Evidence from stock indices

2012, The Quarterly Review of Economics and Finance

We evaluate the performance of several volatility models in estimating one-day-ahead Value-at-Risk (VaR) of seven stock market indices using a number of distributional assumptions. Because all returns series exhibit volatility clustering and long range memory, we examine GARCH-type models including fractionary integrated models under normal, Student-t and skewed Student-t distributions. Consistent with the idea that the accuracy of VaR estimates is sensitive to the adequacy of the volatility model used, we find that AR (1)-FIAPARCH (1,d,1) model, under a skewed Student-t distribution, outperforms all the models that we have considered including widely used ones such as GARCH (1,1) or HYGARCH (1,d,1). The superior performance of the skewed Student-t FIAPARCH model holds for all stock market indices, and for both long and short trading positions. Our findings can be explained by the fact that the skewed Student-t FIAPARCH model can jointly accounts for the salient features of financial time series: fat tails, asymmetry, volatility clustering and long memory. In the same vein, because it fails to account for most of these stylized facts, the RiskMetrics model provides the least accurate VaR estimation. Our results corroborate the calls for the use of more realistic assumptions in financial modeling.

The Quarterly Review of Economics and Finance 52 (2012) 305–321 Contents lists available at SciVerse ScienceDirect The Quarterly Review of Economics and Finance journal homepage: www.elsevier.com/locate/qref Parametric Value-at-Risk analysis: Evidence from stock indices夽 Samir Mabrouk a,∗,1 , Samir Saadi b a b International Finance Group Tunisia, High School of Business, Manouba University, Manouba, Tunisia Queen’s School of Business, Queen’s University, Kingston, Ontario, Canada a r t i c l e i n f o Article history: Received 6 January 2011 Received in revised form 14 February 2012 Accepted 13 April 2012 Available online 11 May 2012 JEL classification: G11 G12 G15 Keywords: Value-at-Risk GARCH Non-normality Long range memory a b s t r a c t We evaluate the performance of several volatility models in estimating one-day-ahead Value-at-Risk (VaR) of seven stock market indices using a number of distributional assumptions. Because all returns series exhibit volatility clustering and long range memory, we examine GARCH-type models including fractionary integrated models under normal, Student-t and skewed Student-t distributions. Consistent with the idea that the accuracy of VaR estimates is sensitive to the adequacy of the volatility model used, we find that AR (1)-FIAPARCH (1,d,1) model, under a skewed Student-t distribution, outperforms all the models that we have considered including widely used ones such as GARCH (1,1) or HYGARCH (1,d,1). The superior performance of the skewed Student-t FIAPARCH model holds for all stock market indices, and for both long and short trading positions. Our findings can be explained by the fact that the skewed Student-t FIAPARCH model can jointly accounts for the salient features of financial time series: fat tails, asymmetry, volatility clustering and long memory. In the same vein, because it fails to account for most of these stylized facts, the RiskMetrics model provides the least accurate VaR estimation. Our results corroborate the calls for the use of more realistic assumptions in financial modeling. © 2012 The Board of Trustees of the University of Illinois. Published by Elsevier B.V. All rights reserved. “Dogmas and doctrines holding that markets worked well and that they were self-correcting once again came to predominate. This time, the theories were more sophisticated, but the underlying assumptions were equally irrelevant. These ideas helped shaped the intellectual milieu which gave rise to the flawed policies that, in turn, gave rise to the crisis.” Joseph E. Stiglitz (2009). 1. Introduction Risk management has become a central issue especially following the recent financial crisis when several financial firms went bankrupt or got bailed out by their governments (e.g. Lehman Brothers, AIG, Royal Bank of Scotland). Indeed, the substantial losses associated with the 2007–2009 financial crisis led to calls for a reassessment of the entire risk management system, including the tools used to measure risk. A powerful risk management approach that gained increasing momentum since its introduction in 1994 is the Value-at-Risk (VaR). VaR provides an estimate 夽 We are grateful to H.S. Esfahani (Editor) and two anonymous referees for their insightful comments and suggestions. ∗ Corresponding author. E-mail addresses: [email protected] (S. Mabrouk), [email protected] (S. Saadi). of the possible loss of a financial portfolio at a specific risk level over a definite holding period. In spite of the shortcomings related to its mathematical properties and the criticisms over its potential destabilizing impact on financial activities, VaR remains the industrial benchmark for measuring risk, and its estimation has again attracted global attention. The aim of this paper is to evaluate the performance of VaR approach under different assumptions of error distribution and advanced volatility modeling, and determine the best model specification that provides the most accurate VaR estimation. A sensible risk measure tool should take into account the stylized fact of financial time series. In fact, several empirical studies have shown that asset returns are skewed, have fat tails and exhibit volatility clustering as well as long memory. Since the introduction of ARCH model, designed by Engle (1982) and then generalized by Bollerslev (1986), the financial econometric literature developed several alternative models to capture volatility clustering in financial time series. For example the GARCH (1,1) is known to successfully capture certain properties of asset returns such as excess kurtosis and volatility clustering (see, for instance, Hansen & Lunde, 2005). However, because it is mainly designed to capture shortrun temporal dependencies in conditional variance, the symmetric GARCH (p,q) models fail to capture long memory and asymmetry in financial times series (e.g. Baillie, Bollerslev, & Mikkelsen, 1996; Bollerslev & Jubinski, 1999; Breidt, Crato, & de Lima, 1998; Davidson, 2004; Ding & Granger, 1996). 1062-9769/$ – see front matter © 2012 The Board of Trustees of the University of Illinois. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.qref.2012.04.006 306 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Since volatility is a key input to estimate VaR, the use of volatility models that take into account the properties of asset returns is crucial for the accuracy of VaR estimation (e.g. Angelidis, Benos, & Degiannakis, 2004; Bali & Theodossiou, 2007; Mabrouk & Aloui, 2010; So & Yu, 2006; Tang & Shieh, 2006; Wu & Shieh, 2007). Accordingly, to compute VaR, we employ two popular models, namely, FIGARCH (Baillie et al., 1996) and HYGARCH (Davidson, 2004). In fact, these models are designed to capture not only volatility clustering but also long memory in assets return volatility. Furthermore, to account for asymmetry in return volatility, we also use FIAPARCH model that was introduced by Tse (1998) as an extension of FIGARCH. Finally, we measure and evaluate VaR under normal distribution as well as two error distributions known to better depict financial time series: Student-t and skewed Studentt. In fact, one of the shortcomings of RiskMetrics, a conventional VaR approach proposed by J.P. Morgan, is the assumption that asset returns are normally distributed. However, asset returns are asymmetric and have fatter tails than normal distribution. Though the unrealistic assumptions, such as normality, are mainly considered to allow for model tractability and to simplify the computational side of the VaR calculation, they induce nontrivial bias in VaR estimation, and thus lead to major financial losses. It is noteworthy that the issue of sensitivity of financial models to pre-determined underlying assumptions has recently attracted much attention. In fact, in his opening plenary keynote address at the American Economic Association 2010 Meeting, Nobel Prize Laureate Joseph E. Stiglitz (2010) asserts that the recent financial crisis serves as a siren call for better allocation of financial economics research efforts in which models are built on more realistic assumptions. In the same vein, Colander et al. (2009) and Eichengreen (2008), among others, are critical of market participants for applying the results of academic research without appropriate reservation. Academics are also blamed for not warning users of the limitations associated with its preferred models. In particular, academics are criticized for excessive reliance on models which ignore the key elements driving outcomes in real-world markets (e.g. Roldán, 2009; Willett, 2009). To establish whether changes in model specification (e.g. error distribution) influence the robustness of estimator inferences, Leamer (1985) recommends that the researcher select alternative assumptions and identify the corresponding interval of inferences. Leamer’s recommendation that the researcher should exhaust all attempts “to combat the arbitrariness associated with the choice of prior distribution” (Leamer, 1986), takes on additional significance when conducting data-driven empirical research. This is an important point in light of the assertion by Colander et al. (2009): “the current approach of using pre-selected models is problematic and we recommend a more data-driven methodology.” In line with Leamer’s (1985) recommendation, we first model conditional variance for seven major stock index returns using different volatility models (e.g. GARCH, HYGARCH, FIAPARCH) and under three alternative distributions (i.e. normal, Student-t, and skewed Student-t). We examine several returns series to make sure that our findings are not the artefact of a specific financial market. We select the best volatility model that fits the data based on several model selection criteria. We then assess the performance of the selected model in estimating VaR for both in-sample and outof-sample periods and for short and long trading positions using failure rate, the Kupiec’s (1995) likelihood ratio test and Engle and Manganelli’s (2004) Dynamic Quantile test. We also examine whether the choice of mean equation influences the accuracy of VaR estimates using different orders of autocorrolation. Our results corroborate the calls for the use of more realistic assumptions in financial modeling. In fact, we find that skewed Student-t FIAPARCH (1,d,1) model provides more accurate estimates of daily Value-at-Risk (VaR) returns of both long and short trading positions than those generated using alternative volatility models and under normal or Student-t distributions. Our findings hold for all the financial markets. This can be explained by the fact that the skewed Student-t FIAPARCH (1,d,1) jointly accounts for the salient features of financial time series: fat tails, asymmetry, volatility clustering and long memory. Furthermore, we find that mean process specification does not play a major role in improving VaR estimates. The remainder of the paper is organized as follows. Section 2 provides a description of the GARCH models used in our analysis. Section 3 introduces the VaR model and describes the evaluation framework for VaR estimates. Section 4 presents preliminary statistics for our dataset while Section 5 provides the results of the empirical investigation of the estimated models. Section 6 concludes the paper. 2. Modeling volatility 2.1. GARCH model Developed by Bollerslev (1986), the GARCH model is a generalization of Engle’s (1982) ARCH model. Assuming that the returns process is expressed as an autoregressive process of order k, rt = ς0 + k  i=1 ςi rt−i + εt (1) Conditional on information set up to time t − 1, εt is an i.i.d. random variable with mean 0 and variance t2 , a GARCH (p,q) model is expressed as follows: t2 = ω + q  i=1 ˛i ε2t−i + p  2 ˇj t−j (2) i=1 The lag operator allows us to specify GARCH model as: t2 = ω + ˛(L)ε2t + ˇ(L)t2 (3) where ˛(L) = ˛1 L + ˛2 L2 + · · · + ˛q Lq and ˇ(L) = ˇ1 L + ˇ2 L2 + · · · + ˇp Lp Bollerslev (1986) showed that the GARCH model is a short memory model since its autocorrelation function decays slowly with a hyperbolic rate. 2.2. RiskMetrics model Since its introduction in 1994 by the risk management group at J.P. Morgan, RiskMetrics has become the standard in the field of risk management and this despite its several limitations, such as assuming that the error terms are normally distributed. The RiskMetrics model is an Integrated GARCH (1,1) where ARCH and GARCH parameters are pre-specified. RiskMetrics model can be written as follows: 2 t2 = ω + (1 − )ε2t + t−1 (4) where ω = 0 and  fixed at 0.94 for daily data and 0.97 for weekly data. Thus there is no estimation of volatility parameters required in the context of RiskMetrics approach. 2.3. The Fractional Integrated GARCH model Baillie et al. (1996) proposed a Fractional Integrated GARCH (FIGACH) model to capture the documented evidence of long memory in financial time series. The FIGARCH model can distinguish between short memory and infinite long memory in the conditional S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 variance, and this thanks to the fractionary parameter d. Formally, the FIGARCH(p, d, q) process is specified as follows: [ϕ(L)(1 − L) d ]ε2t =ω + [1 − ˇ(L)](ε2t − t2 ) (5) distribution is defined as follows:  LStud = T ln  or − t2 = ω + ˇ(L)t2 + [1 − ˇ(L)]ε2t − ϕ(L)(1 − L)d ε2t = ω[1 − L]−1 + (L)ε2t (6) ∞ where (L) is the lag-operator, (L) =  Li and 0 ≤ d ≤  is an i=1 i infinite summation which, in practice, has to be truncated. According to Baillie et al. (1996), (L) should be truncated at 1000 lags. (1 − L)d is the fractional differencing operator and it is defined as follows: (1 − L)d = ∞  k=0 −  (d + 1)Lk 1 = 1 − dL − d(1 − L)L2 2  (k + 1) (d − k + 1) ∞  1 ck (d)Lk d(1 − d)(2 − d)L3 − · · · = 1 − 6 (7) k=1 Another popular model known for capturing long memory in conditional volatilities is the hyperbolic GARCH model (HYGARCH). Designed by Davidson (2004), the HYGARCH model is built to test whether the non-stationarity of the FIGARCH model holds. The HYGARCH model extends the conditional variance of the FIGARCH model by introducing the weights in the difference operator. The HYGARCH model can be written as follows: 2 − ln  1 2 t=1  2   T  ln  + ln 2.4. The hyperbolic GARCH model  + 1 ln(t2 ) + (1 + ) ln −  1 ln[( − 2)] 2 1+ zt2 2 t ( − 2) (11) where 2 <  ≤ ∞ and  (·) is the gamma function. In contrast to the normal distribution, the Student-t distribution is estimated with an additional parameter , which stands for the number of degrees of freedom measuring the degree of fat-tails in the density. The deviation from the normal distribution in asset returns is mainly due to excess kurtosis and excess skewness. The Student-t is successful in depicting the excess kurtosis in financial time series but not excess skewness. To jointly account for the excess skewness and kurtosis, we consider the skewed Student-t distribution proposed by Lambert and Laurent (2001). Let z∼SKST(0, 1, k, ), the log-likelihood of the skewed Student-t distribution (SKST) L is defined as: LSkst = T where c1 (d) = d, c2 (d) = (1/2)d(1 − d), etc. 307   + 1 2 2 k + (1/k)   +(1 + ) ln 1 + − ln   2  + ln(s) 1+ − − 1 ln[( − 2)] 2 T  1 ln(t2 ) 2 t=1 (szt + m)2 ( − 2) k−2It (12) where It = 1 if zt ≥ m/s or It = −1 if zt < m/s, k is an asymmetry Thus the HYGARCH model is a generalized FIGARCH since it nests to GARCH when ˛ = 0 and to FIGARCH when ˛ = 1 parameter. The constants m = m(k, ) and s = s2 (k, ) are the mean and standard deviations of the skewed Student-t distribution: √    (( − 1)/2)  − 2 1 m(k, ) = (13) k− √ k  (/2) 2.5. The fractional integrated asymmetric power ARCH model s2 (k, v) = t2 = ω[1 − ˇ(L)] −1 + {1 − [1 − ˇ(L)] −1 (L)[1 + ˛{(1 − L)d }]}ε2t (8) Tse (1998) extended the FIGARCH (p,d,q) model in order to jointly account for volatility asymmetry and long memory, and this by adding the function (|εt | − εt )ı of the APARCH process to the FIGARCH process. Formally, the FIAPARCH (p,d,q) can be expressed as follows: tı = ω[1 − ˇ(L)] −1 + {1 − [1 − ˇ(L)] −1 (L)(1 − L)d }(|εt | − εt )ı (9)  k2 +  1 − 1 − m2 k2 (14) The value of ln(k) can also represent the degree of asymmetry in the residual distribution. We note that when ln(k) = 0, the skewed Student-t distribution equals the general Student-t distribution, z∼ST (0, 1, ). 3. The Value-at-Risk where ı, and ␭ are the model parameters. The FIAPARCH process nests the FIGARCH process when ␥ = 0 and ı = 2. Thus, the FIGARCH process is a sample case of the FIAPARCH model. In this section we present the VaR model under a FIAPARCH model with skewed Student-t distribution innovation. Let’s consider that 2.6. The error’s density models rt = t + εt Let z∼N(0, 1) be a random variable, the log-likelihood of the normal distribution can be written as follows: t =  + T LNorm = − 1 [ln(2) + ln(t2 ) + zt2 ] 2 (10) t=1 where T is the number of observations. Several studies, however, have shown that asset returns have fatter tails than normal distribution. To account for this property of financial time series, we consider Student-t: Consider the random variable z∼ST (0, 1, ), the log-likelihood function of the Student-t m  i=1 (15) i rt−i + n  j εt−j (16) j=1 The εt = zt t is governed by a FIAPARCH (p,d,q) process and the innovations are assumed to follow the skewed Student-t distribution if: f (zt |k, v) = ⎧ 2 ⎪ ⎨ k + (1/k) sg(k(szt + m)|v) ⎪ ⎩ 2 sg(k(szt + m)/k|v)t k + (1/k) , if zt < −m/s zt ≥ −m/s (17) 308 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 In the above equation, g(·|v) denotes the symmetrical Student-t density and k is the asymmetry parameter. The estimated VaR for the long and short trading positions can be expressed as follows: ˛ = P(rt < VaRt,L ) = P ˛ = P(rt > VaRt,s ) = P r −  t t t r −  t t t < >  VaRt,L − t t VaRt,s − t t  (18) (19) Table 1 Data. Stock index Sample period Observations DAX DOW JONES NASDAQ NIKKEI CAC40 FTSE100 S&P500 01/02/1990 to 10/10/2008 01/02/1990 to 10/10/2008 01/02/1990 to 10/10/2008 01/02/1990 to 10/10/2008 01/02/1990 to 10/10/2008 01/02/1990 to 10/10/2008 01/02/1990 to 10/10/2008 4498 4734 4720 4607 4678 4727 4720 VaRt,L and VaRt,s , in Eqs. (18) and (19), are for the long and the short trading positions, respectively. More specifically VaRt,L and VaRt,s are as follows: VaRt,L = t + st˛ (v, k)t (20) VaRt,s = t + st1−˛ (v, k)t (21) where st˛ (v, k) is the left quantile at the ˛% of the skewed Student-t distribution innovation. Correspondingly, st1−˛ (v, k) is the right quantile of the skewed Student-t distribution.1 According to Lambert and Laurent (2001) and Wu and Shieh (2007), we can compute the one-day-ahead VaR estimated at time (t − 1) for the long and the short trading positions. Under the hypothesis of skewed Student-t distribution, the one-day-ahead VaR for the long and the short trading positions are as follows:  VaR t + st˛ (v, k)t t,L =   t + st1−˛ (v, k)t VaR t,s =  1 if rt+1 < VaRt+1|t(˛) 0 if T −N } + 2 log  N  N T 1−  T −N  N T (25) Under the null hypothesis, LRUC has a 2 (1) as an asymptotical distribution. Thus, a preferred model for VaR prediction should provide the property that the unconditional coverage measured by p = E(N/T ) equals the desired coverage level p0 . Engle and Manganelli developed the Dynamic Quantile (DQ) test building upon a linear regression model based on the process of centered hit function: ı˛ t = Hitt (˛) ≡ I(yt < −VaRt (˛)|˝t−1 ) − ˛ (23) Conditional on pre-sample values, the dynamic of the hit function is modeled as: ı˛ t = 0 + The accuracy of VaR estimates is sensitive to the adequacy of the volatility model used. It is therefore important to evaluate the performance of VaR model given the pre-selected volatility model. We do using two approaches. The first approach consists at computing the empirical failure rate, both for the left and right tails of the returns distribution. The prescribed probability ranges from 0.25% to 5%. The failure rate can be defined as the number of times in which returns exceed (in absolute value) the forecasted VaR. If the model is correctly specified, then the failure rate is equal to the specified VaR’s level. The second approach in examining the accuracy of VaR estimate consists at backtesting VaR using Kupiec LR Unconditional Coverage test and the Conditional Coverage test proposed by Engle and Manganelli (2004). In order to test the accuracy and to evaluate the performance of the model-based VaR estimates, Kupiec (1995) provided a likelihood ratio test (LRUC ) to examine whether the failure rate of the model is statistically equal to the expected one (unconditional covT erage). Consider that N = I is the number of exceptions in the t=1 t sample size T, then It+1 = LRUC = −2 log{˛N (1 − ˛0 ) 0 (22) 3.1. Assessing the accuracy for VaR estimates  likelihood ratio statistic in the presence of the null hypothesis is given by: (24) rt+1 ≥ VaRt+1|t(˛) follows a binomial distribution, N∼B(T, ˛). If p = E(N/T ) is the expected exception frequency (i.e. the expected ratio of violations), then the hypothesis for testing whether the failure rate of the model is equal to the expected one is expressed as follows: H0 : ˛ = ˛0 · ˛0 . is the prescribed VaR level. Thus, the appropriate 1 For more details, see Lambert and Laurent (2001), Giot and Laurent (2003) and Wu and Shieh (2007). p  i=1 (˛) i ıt=i + m  =1 () ϑi ıt=i + t (26) (27) where t is an IID process. The DQ test is defined under the hypothesis that the regressors in Eq. (27) have no explanatory power: T H0 =  = (0 , 1 , . . . , p , ϑ0 , ϑ1 , . . . , ϑm ) = 0 For backtesting, the DQ test statistic, in association with Wald statics, is as follows: DQ = ˆ T XT  ˆ ℓ  −→21+p+m ˛(1 − ˛) (28) where X denotes he regressors matrix in Eq. (27) 4. Data and preliminary analysis Our sample consists of daily closing prices of seven stocks indices obtained from DataStream: Dow Jones, NASDAQ 100, and S&P 500 from The U.S., FTSE 100 from the U.K., DAX 30 of Germany, the CAC40 of France and the NIKKEI 225 of Japan. The sample period and the number of observations are indicated in Table 1. The daily returns are defined as follows: rt = 100 ∗ log  S  t St−1 where St denotes the daily price index. Table 2 reports the descriptive statistics for our sample. Except for the Nikkey stock index, all the stock index returns have a positive mean. Furthermore, all the return series are not normally distributed as it is indicated by the 3rd and the 4th moment. More precisely, the returns series are skewed and fat tailed. This is also confirmed by Jarque–Bera test statistic. Fig. 1 displays the daily returns of each index. It is clear that large price changes tend to follow large changes, and small changes tend to follow S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Daily returns-CAC40 309 Daily returns -DAX 15 8 6 10 4 2 5 0 0 -2 -4 -5 -6 -8 -10 -10 -15 -12 92 94 96 98 00 02 04 06 08 92 94 96 Daily returns - FTSE100 98 00 02 04 06 08 04 06 08 Daily returns -DOW JONES 12 8 10 6 8 6 4 4 2 2 0 0 -2 -2 -4 -4 -6 -6 -8 -10 90 92 94 96 98 00 02 04 06 08 -8 90 92 94 Daily returns -NASDAQ 96 98 00 02 Daily returns -S&P500 15 6 4 10 2 5 0 0 -2 -4 -5 -6 -10 -8 -15 -10 90 92 94 96 98 00 02 04 06 08 90 92 94 96 98 00 02 Daily returns –NIKKEI 225 15 10 5 0 -5 -10 90 92 94 96 98 00 02 04 06 08 Fig. 1. Daily returns of equity indices (CAC 40, DAX, FTSE 100, Dow Jones, NASDAQ, S&P500, Nikkei 225). 04 06 08 310 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Table 2 Descriptive statistics. Stock index Mean Mediane Maximum Minimum SD Skewness Kurtosis Jarque–Bera DAX DOW JONES NASDAQ NIKKEI CAC40 FTSE100 S&P500 0.0262 0.0239 0.0266 −0.0317 0.0112 0.0120 0.0198 0.0741 0.0476 0.1014 −0.0232 0.0591 0.0262 0.0435 7.270 6.139 14.023 12.427 11.928 10.396 5.571 −10.374 −7.777 −10.683 −8.801 −12.595 −8.178 −9.114 1.373 1.009 1.578 1.395 1.464 1.105 1.042 −0.394 −0.387 −0.291 0.158 −0.362 −0.046 −0.432 7.673 8.139 10.165 6.324 9.924 8.129 8.630 4209 5327 10,159 2140 9448 5183 6382 Notes: S.D. is the standard deviation. For all the time series, the descriptive statistics for daily returns are expressed in percentage. Table 3 Unit root and stationarity tests. Index ADF PP KPSS DAX DOW JONES NASDAQ NIKKEI CAC40 FTSE100 5&P500 −46.91 −48.81 −50.13 −38.96 −50.22 −50.55 −49.29 −66.24 −68.53 −71.4 −64.96 −74.65 −73.64 −69.68 0.2586 0.3997 0.3470 0.1224 0.2100 0.2617 0.4558 existence of long memory we employ two long-range memory tests: the log-periodogram regression (GPH) of Geweke and PorterHudak (1983) and the Gaussian semi-parametric estimate (GSP) of Robinson and Henry (1999). Similar to several previous studies, we use the absolute returns and the daily squared volatility returns as proxies for daily volatility. We employ the following three bandwidth for GHP test: m = T 0.5 ; m = T 0.6 and m = T 0.7 . As for GSP test, we use m = T /2; m = T /4 and m = T /8. Table 4 below reports the results of the long memory tests. Both GPH and GSP test statistics suggest the non-rejection of the null hypothesis of short memory in returns (there is no persistence in the conditional mean), but not for the two proxies of volatility (squared returns and absolute returns). In fact, both test statistics indicate strong evidence of long range memory in the conditional variance of our series. Thus, it appears that the autocorrelation function for both squared returns and absolute returns decayed very slowly at long time lags, a property of long memory processes. Therefore, the fractionally integrated GARCH-class models are recommended to model the dynamics of our returns series. Notes: MacKinnon’s 1% critical value is −3.435 for the ADF and PP tests. The KPSS critical value is 0.739 at the 1% significance level. small changes. This is a property of asset prices, volatility clustering (a type of heteroscedasticity) that each index seems to exhibit. This graphical evidence is an indication of the presence of ARCH effect in our daily returns series that should be accounted for when estimating VaR. To have a better understanding of the behavior of the returns series, it is important to examine whether they are stationary. To do so, we employ three widely used tests: the Augmented Dickey–Fuller (1979) (ADF) unit root test, the Phillips–Perron (1988) (PP) unit root test and Kwiatkowski, Phillips, Schmidt, and Shin (1992) (KPSS) stationarity test. The ADF and PP unit root test results, reported in Table 3, indicate that, for all the return series, the null hypothesis of presence of unit root is rejected. In the same vein, the KPSS test indicates that all the returns series are stationary. Hence, our data sample is appropriate for empirical analysis. While our preliminary data analysis suggests using a GARCH type model to estimate VaR, a test of the presence of long range memory is required to refine the model selection. To examine the 5. Empirical results 5.1. Estimates GARCH-type models In this sub-section we try to identify the volatility model that best fits our returns data. In the next sub-section we evaluate the accuracy of the selected model in estimating VaR of each of the seven returns series, and this for short and long trading positions. Before examining the choice of volatility model we first determine Table 4 Long range memory tests. Panel a GPH test m = T0.5 m = T0.6 m = T0.7 GSP test m = T/2 m = T/4 m = T/8 Panel b GPH Test m = T05 m = T06 m = T0J GSP Test m = T/2 m = T/4 m = T/8 rt2 |rt| DAX DOW JONES NASDAQ NIKKEI DAX DOW JONES NASDAQ NIKKEI 0.62 0.52 0.45 0.48 0.44 0.43 0.49 0.47 0.38 0.25 0.35 0.29 0.59 0.47 0.41 0.35 0.35 0.37 0.45 0.38 0.36 0.26 0.27 0.24 0.303 0.394 0.501 0.271 0.360 0.480 0.282 0.366 0.447 0.276 0.372 0.455 0.260 0.315 0.424 0.232 0.280 0.389 0.237 0.288 0.355 0.198 0.282 0.322 |rt| CAC40 FTSE 100 S&P 500 rt2 CAC40 FTSE 100 S&P 500 0.50 0.44 0.39 0.45 0.40 0.42 0.38 0.26 0.24 0.33 0.29 0.28 0.36 0.33 0.32 0.20 0.16 0.17 0.281 0.350 0.467 0.289 0.380 0.463 0.276 0.367 0.465 0.20 0.222 0.289 0.231 0.298 0.351 0.245 0.282 0.380 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 311 Table 5 AR (1)-RiskMetrics model estimation. DAX Cst(M) AR (1) ˛1 ˇ1 ln(ℓ) AIC SIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) DOW JONES *** 0.05 (0.02) 0.03** (0.01) 0.06 0.94 −7054.73 3.13 3.14 17.83 6.16 10.39 0.42 137.42*** *** 0.04 (0.01) 0.02 (0.01) 0.06 0.94 −6152.3 2.60 2.606 21.65 12.53 18.21 0.51 128.66*** NASDAQ NIKKEI ** 0.05 (0.02) 0.02 (0.01) 0.06 0.94 −7707.8 3.269 3.274 30.74 22.99 29.7 1.67 153.6*** 0.01 (0.02) −0.03** (0.01) 0.06 0.94 −7764.77 3.372 3.378 21.26 17.02 25.99 0.94 77.02*** CAC40 0.03 (0.02) −0.06*** (0.01) 0.06 0.94 −7836.76 3.352 3.357 18.74 25.65 31.41 1.78 121.89*** FTSE 100 S&P 500 *** 0.03 (0.01) −0.06*** (0.02) 0.06 0.94 −6565.55 2.779 2.785 26.57 30.03 39.35 1.78 94.89*** 0.04*** (0.01) 0.0003 (0.02) 0.06 0.94 −6206.49 2.631 2.736 34.98 11.53 17.58 0.49 157.69*** Notes: ln(ℓ) is the value of the maximized log-likelihood. AIC is the Akaike Information Criterion and SIC is the Schwarz Information Criterion. Q(20) and Q2 (20) are the Box–Pierce statistics for remaining serial correlation for respectively standardized and squared standardized residuals. RBD(20) is the residual based diagnostic for conditional heteroscedasticity, using 20 lags. The ARCH(10) is LM-ARCH test of using 10 lags. P(60) is the Pearson goodness-of-fit statistic for 60 cells. * Significance level at 10%. ** Significance level at 5%. *** Significance level at 1%. k, the order of autocorrelation in the mean equation as indicated in Eq. (1). Evidence from graphic representation of Akaike Information Criterion (AIC) suggests that k = 1 provides the lowest AIC value. The choice of k = 1 is also confirmed by the Modified Qstatistics showing the residuals of the AR (1) being white noise, and which in turn suggest that the AR (1) model accounts for all the linearity dependence (autocorrelation) in each of the seven index returns.2 The autocorrelation may exist due to institutional factors such as non-synchronous trading which may induce priceadjustment.3 Based on the sample characteristics identified in Section 4, we consider four widely used volatility models and then compare their performances based on the value of the maximized log-likelihood function, Akaike Information Criterion (AIC) and Schwarz Information Criterion (SIC). The models are: GARCH, FIGARCH, FIAPARCH and HYGARCH models under normal, Studentt and skewed Student-t distributions. For the sake of comparison, we also consider RiskMetrics which was suggested by J.P. Morgan when they introduced VaR. As indicated above, RiskMetrics model is a pre-specified IGARCH (1,1) model where the GARCH coefficient (ˇ1 ) is set at 0.94 with daily observations and 0.97 for weekly observations. Table 5 reports the estimation results of AR (1)-RiskMetrics model where set ˇ1 = 0.94 since we are dealing with daily return series. Consisting with the shortcomings of RiskMetrics approach with respect to modeling volatility of financial time series, all the diagnostic tests indicate that the RiskMetrics specification is not appropriate (Box–Pierce tests using standardized residuals and squared standardized residuals, the RBD test, the ARCH-LM test, and the Pearson goodness-of-fit). This is in fact not surprising given the rigidity of the RiskMetrics model and the fact that it can only be assessed under a normal distribution. We address this limitation by considering GARCH (1,1) under normal, as well as Student-t and skewed Student-t distributions. Several empirical studies show that GARCH (1,1) performs particularly well in capturing some of the salient features of returns series. For instance, Hansen and Lunde (2005) show that GARCH (1,1) outperforms several GARCH type models and specifications in capturing volatility clustering in finance returns series.4 Table 6 (panels a & b) reports the estimation results of a GARCH (1,1) process for all the returns series under the assumption that the innovations follow either a normal distribution, Student-t or skewed Student-t. The coefficients of the conditional variance equation are significant at 1% level implying a strong support for the ARCH and GARCH effects. Furthermore, the condition for the existence of conditional variance is justified since for all the index returns we have that ˛1 + ˇ1 < 1. Interestingly, all the model selection criteria (i.e. maximized log-likelihood function, AIC and SIC) indicate that AR (1)-GARCH (1,1) model under a skewed Student-t distribution provides the best fit for each of the seven index returns. It is noteworthy, however, that the sum of the parameters estimated by the variance equation is close to one. A sum ˛1 + ˇ1 near one is an indication of a covariance stationary model with a high degree of persistence in the conditional variance. The sum ˛1 + ˇ1 is also an estimation of the rate at which the response function decays on daily basis. Since the rate is high, the response function to shocks is likely to die slowly. For instance, in the case of Dow Jones Index, under skewed Student-t distribution, ˛1 + ˇ1 = 0.99 which means that a month after an initial shock 74% (or 0.9930 ) of the impact remains in effect. Even six months later, 16% (or 0.99180 ) of initial shock remains persistent. The evidence of high volatility persistence and long memory in the GARCH (1,1) model suggest that a FIGARCH (p,d,q) model may be more adequate to describe the data. Table 7 provides the estimation results of FIGARCH (1,d,1) under the three aforementioned alternative distributions. Consistent with the results from Table 4, all times series are governed by long memory process. In fact, the fractionary integrated parameter d ranges from 0.44 to 0.65. As expected, the FIGARCH (1,d,1) model outperform GARCH and RiskMetrics models as it is indicated by each of the model selection criterion. Interestingly, the skewed Student-t distribution provides the most adequate FIGARCH model for the seven time series outperforming the FIGARCH models under normal and Student-t distributions. 2 For brevity, we do not report the graphs of AIC and the Modified Q-statistics, but they are available upon request. 3 Lo and Mackinlay (1990) argue that individual stock prices trading at different frequencies can lead to a spurious positive autocorrelation in market-index returns. 4 It is noteworthy that Hansen and Lunde (2005) did not compare the performance of GARCH (1,1) to those of volatility models designed to capture long range memory, such as FIGARCH and HYGARCH. We also augment Hansen and Lunde’s work by considering skewed Student-t distribution. 312 Table 6 AR (1)-GARCH (1,1) model estimation. Panel a DAX N Cst(M) AR (1) ˛1 ˇ1  ln(ℓ) AIC SIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) 006*** (0.01) 0.03** (0.01) 0.08*** (0.01) 0.90*** (0.01) – – – – −6997 3.11 3.120 18.57 5.66 5.60 0.35 137.02*** 0.08*** (0.01) 0.02* (0.01) 0.07*** (0.01) 0.92*** (0.008) 7.95*** (1.08) −0.11*** – −6883 3.06 3.072 19.92 6.04 5.3 0.34 100.2*** SKt N 0.06*** (0.01) 0.01 (0.01) 0.07*** (0.08) 0.92*** (0.08) 8.47*** (1.18) – (0.02) −6870 3.058 3.068 22.36 6.02 5.4 0.35 68.02** 0.04*** (0.01) 0.02* (0.01) 0.06*** (0.01) 0.92*** (0.01) – – −0.07*** – −6113 2.585 2.591 21.42 11.96 12.41 0.55 136.7*** NASDAQ t SKt 0.05*** (0.01) 0.008 (0.01) 0.06*** (0.008) 0.93*** (0.009) 7.53*** (0.85) – – −6018 2.545 2.553 23.18 12.08 12.52 0.53 104.9*** 0.04*** (0.01) 0.002 (0.01) 0.06*** (0.008) 0.93*** (0.08) 7.87*** (0.90) −0.16*** (0.01) −6011 2.5452 2.5532 24.38 12.09 12.57 0.53 83.3** N 0.06*** (0.01) 0.02** (0.01) 0.10*** (0.02) 0.88*** (0.02) – – – – −7656 3.247 3.254 28.47 13.51 11.81 0.76 176.6*** NIKKEI t SKt 0.09*** (0.01) 0.02*** (0.01) 0.07*** (0.01) 0.92*** (0.01) 7.42*** (0.82) – – −7549 3.202 3.211 28.63 19.49 18.82 1.32 109*** 0.06*** (0.01) 0.010 (0.01) 0.07*** (0.01) 0.92*** (0.01) 8.01*** (0.93) −0.01 (0.02) −7521 3.191 3.201 41.43 18.04 17.43 1.19 78.4** N 0.015 (0.01) 0.04*** (0.01) 0.09*** (0.01) 0.88*** (0.01) – – – −7712 3.350 3.357 16.46 11.14 14.87 0.48 84*** t SKt 0.004 (0.009) 0.03*** (0.009) 0.08*** (0.009) 0.90*** (0.009) 10.15*** (1.48) 0.001 (0.009) 0.02** (0.009) 0.08*** (0.009) 0.90*** (0.009) 10.15*** (1.47) – −766 3.329 3.336 18.46 14.12 13.81 0.43 57*** (0.02) −76,600 3.328 3.338 18.72 14.1 13.79 0.43 63*** Panel b CAC40 Cst(M) AR (1) ˛1 ˇ1   ln(ℓ) AIC SIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) FTSE 100 S&P 500 N t SKt N t SKt N 0.04*** (0.01) −0.06*** (0.01) 0.11*** (0.02) 0.87*** (0.02) – – – – −7765 3.322 3.329 19.70 16.71 15.66 0.86 117.84*** 0.05*** (0.01) −0.06*** (0.01) 0.08*** (0.01) 0.90*** (0.01) 7.85*** (0.95) – – −7663 3.278 3.287 19.75 21.97 20.84 1.32 72.90*** 0.03*** (0.01) −0.07*** (0.01) 0.08*** (0.01) 0.90*** (0.01) 8.27*** (1.02) –0.10*** (0.02) −7651 3.274 3.283 21.03 21.53 20.57 1.30 51.20*** 0.03*** (0.01) −0.05*** (0.01) 0.09*** (0.01) 0.89*** (0.01) – – – – −6526 2.763 2.770 26.92 23.40 22.61 1.07 103.04*** 0.04*** (0.01) −0.06*** (0.01) 0.08*** (0.01) 0.90*** (0.01) 9.52*** (1.27) – – −6466 2.738 2.746 27.37 23.82 23.80 1.17 67.40*** 0.03*** (0.01) −0.07*** (0.01) 0.08*** (0.01) 0.90*** (0.01) 8.87*** (1.40) −0.06** (0.01) −6460 2.736 2.746 27.76 23.94 23.87 1.18 51.66*** 0.04*** (0.01) 0.0002 (0.01) 0.06*** (0.01) 0.93*** (0.01) – – – – −6173 2.618 2.624 32.83 12.57 13.14 0.70 170.25*** t 0.05*** (0.01) −0.011 (0.01) 0.05*** (0.008) 0.94*** (0.009) 7.07*** (0.77) – – −6077 2.577 2.586 35.39 13.34 13.85 0.75 75.88*** SKt 0.04*** (0.01) −0.017 (0.01) 0.05*** (0.008) 0.94*** (0.009) 7.32*** (0.81) −0.06** (0.01) −6072 2.576 2.585 36.53 13.16 13.71 0.73 70.16** Notes: ln(ℓ) is the value of the maximized log-likelihood. AIC is the Akaike (1974) Information Criterion and SIC is the Schwarz Information Criterion. Q(20) and Q2 (20) are the Box–Pierce statistics for remaining serial correlation for respectively standardized and squared standardized residuals. RBD(20) is the residual based diagnostic for conditional heteroscedasticity, using 20 lags. The ARCH(10) is LM-ARCH test of Engle (1982), using 10 lags. P(60) is the Pearson goodness-of-fit statistic for 60 cells. Figures between parentheses are the standard errors. N, t and SKt are respectively normal, Student-t and the skewed Student-t distribution. * Significance level at 10%. ** Significance level at 5%. *** Significance level at 1%. S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321  DOW JONES t Table 7 AR (1)-FIGARCH (1,d,1) model estimation. Panel a DAX DOW JONES N Cst(M) AR (1) d ϕ1   ln(ℓ) AIC SIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) 0.06*** (0.01) 0.03** (0.01) 0.51*** (0.1) 0.13*** (0.05) 0.59*** (0.09) – – – – −6987 3.10 3.118 18.81 4.61 4.85 0.21 154.3*** SKt 0.08*** (0.01) 0.02* (0.007) 0.65*** (0.07) 0.1*** (0.03) 0.72*** (0.05) 8.04*** (1.01) – – −6876 3.06 3.070 19.82 7.06 5.56 0.4 109.2*** N 0.06*** (0.01) 0.01* (0.01) 0.66*** (0.07) 0.11*** (0.03) 0.74*** (0.05) 8.47*** (1.1) −0.10*** (0.02) −6864 3.055 3.067 22.19 7.18 5.65 0.4 75.36*** 0.04*** (0.01) 0.02* (0.01) 0.51*** (0.08) 0.22*** (0.04) 0.68*** (0.05) – – – – −6107 2.582 2.590 21.07 12.33 13.07 0.56 137*** NASDAQ t SKt 0.05*** (0.01) 0.008 (0.01) 0.52*** (0.06) 0.20*** (0.03) 0.70*** (0.04) 7.52*** (0.81) – – −6009 2.541 2.551 22.98 13.11 13.82 0.62 81.9*** 0.04*** (0.01) 0.001 (0.01) 0.53*** (0.06) 0.20*** (0.03) 0.70*** (0.04) 7.8*** (0.86) −0.07*** (0.01) −6003 2.539 2.550 24.28 12.98 13.69 0.6 80.8*** NIKKEI N 0.07*** (0.01) 0.03** (0.01) 0.45*** (0.07) 0.28*** (0.07) 0.58*** (0.09) – – – – −7637 3.240 3.248 31.55 8.18 8.18 0.33 143*** t 0.09*** (0.01) 0.03** (0.01) 0.46*** (0.05) 0.27*** (0.05) 0.63*** (0.06) 7.78*** (0.82) – – −7537 3.198 3.207 31.18 10.94 11.24 0.62 104*** SKt N 0.06*** (0.01) 0.015 (0.01) 0.46*** (0.05) 0.28*** (0.05) 0.63*** (0.06) 8.43*** (0.94) −0.15*** (0.02) −7510 3.187 3.198 33.68 9.88 10.34 0.51 50.7*** 0.017 (0.01) 0.04*** (0.01) 0.50*** (0.08) 0.18*** (0.05) 0.60*** (0.08) – – – – −7710 3.349 3.358 17.16 13.6 13.84 0.26 794*** t SKt 0.005 (0.01) 0.02*** (0.01) 0.61*** (0.09) 0.16*** (0.04) 0.70*** (0.06) 10.05*** (1.49) – – −7659 3.328 3.337 19.10 13.41 13.06 0.35 61.6*** 0.002 (0.01) 0.02*** (0.01) 0.61*** (0.09) 0.16*** (0.04) 0.7*** (0.06) 10.06*** (1.4) −0.01 (0.02) −7658 3.327 3.339 19.37 13.42 13.03 0.35 61.4*** Panel b CACAO Cst(M) AR (1) d ϕ1 ˇ1   ln(ℓ) AIC BIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) FTSE 100 S&P 500 N t SKt N t SKt N t SKt 0.05*** (0.01) −0.06*** (0.01) 0.56*** (0.08) 0.20*** (0.06) 0.64*** (0.07) – – – – −7760 3.320 3.328 19.67 15.43 15.06 0.82 129.13*** 0.05*** (0.01) −0.06*** (0.01) 0.58*** (0.06) 0.19*** (0.03) 0.70*** (0.04) 7.81*** (0.92) – – −7655 3.276 3.285 20.24 21.24 20.33 1.40 69.23*** 0.03*** (0.01) −0.07*** (0.01) 0.59*** (0.06) 0.20*** (0.04) 0.71*** (0.04) 8.20*** (0.99) −0.09*** (0.02) −7644 3.271 3.282 20.40 20.09 19.14 1.29 49.32*** 0.03*** (0.01) −0.05*** (0.01) 0.57*** (0.06) 0.14*** (0.05) 0.63*** (0.05) – – – – −6518 2.760 2.768 27.98 20.74 21.03 0.95 96.64*** 0.04*** (0.01) −0.06*** (0.01) 0.55*** (0.06) 0.16*** (0.05) 0.64*** (0.05) 9.50*** (1.24) – – −6460 2.736 2.745 28.67 20.57 21.25 0.95 67.58*** 0.03*** (0.01) −0.07*** (0.01) 0.55*** (0.06) 0.16*** (0.05) 0.64*** (0.05) 9.83*** (1.36) −0.06*** (0.02) −6455 2.734 2.745 29.02 20.63 21.20 0.95 55.26*** 0.04*** (0.01) 0.001 (0.01) 0.44*** (0.06) 0.16*** (0.09) 0.57*** (0.09) – – – – −6165 2.615 2.623 34.28 12.37 13.13 0.76 151.59*** 0.05*** (0.01) −0.012 (0.01) 0.48*** (0.05) 0.18*** (0.05) 0.64*** (0.05) 7.27*** (0.74) – – −6068 2.574 2.583 36.46 15.22 16.40 1.02 83.58*** 0.04*** (0.01) −0.018 (0.01) 0.48*** (0.05) 0.17*** (0.05) 0.64*** (0.05) 7.47*** (0.77) −0.06*** (0.01) −6062 2.572 2.583 37.97 14.74 15.91 0.97 76.13*** 313 Notes: ln(ℓ) is the value of the maximized log-likelihood. AIC is the Akaike (1974) Information Criterion and SIC is the Schwarz Information Criterion. Q(20) and Q2 (20) are the Box–Pierce statistics for remaining serial correlation for respectively standardized and squared standardized residuals. RBD(20) is the residual based diagnostic for conditional heteroscedasticity, using 20 lags. The ARCH(10) is LM-ARCH test of Engle (1982), using 10 lags. P(60) is the Pearson goodness-of-fit statistic for 60 cells. Figures between parentheses are the standard errors. N, t and SKt are respectively normal, Student-t and the skewed Student-t distribution. * Significance level at 10%. ** Significance level at 5%. *** Significance level at 1%. S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 ˇ1 t 314 Table 8 AR (1)-HYGARCH (1,d,1) model estimation. Panel a DAX Cst(M) AR (1) d ϕ1 ˇ1   ln(ℓ) AIC SIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) NASDAQ t SKt N t SKt 0.06*** (0.01) 0.03** (0.01) 0.56*** (0.11) 0.12*** (0.05) 0.61*** (0.09) −0.02 (0.02) – – – 0.08*** (0.01) 0.02* (0.01) 0.64*** (0.07) 0.11*** (0.03) 0.72*** (0.05) 0.003 (0.01) 7.98*** (1.07) – 0.06*** (0.01) 0.015 (0.01) 0.66*** (0.07) 0.11*** (0.03) 0.74*** (0.05) −0.0005 (0.01) 8.48*** (1.18) −0.10*** 0.04*** (0.01) 0.02* (0.01) 0.56*** (0.01) 0.20*** (0.05) 0.70*** (0.06) −0.01 (0.02) – – – 0.05*** (0.01) 0.008 (0.01) 0.51*** (0.07) 0.21*** (0.04) 0.69*** (0.04) 0.005 (0.05) 7.47*** (0.84) – 0.04*** (0.01) 0.001 (0.01) 0.52*** (0.07) 0.20*** (0.04) 0.70*** (0.04) 0.0007 (0.02) 7.8*** (0.89) −0.07*** – −6986 3.109 3.119 18.64 4.53 4.45 0.20 155.5*** – −6876 3.061 3.072 19.86 7.07 5.54 0.4 109.5*** (0.02) −6864 3.056 3.068 22.19 7.18 5.65 0.41 76.94*** – −6106 2.582 2.592 20.86 12.29 12.99 0.55 115.9*** – −6009 2.542 2.553 23.08 13.08 13.75 0.62 86.6*** NIKKEI N (0.01) −6003 2.540 2.552 24.29 12.98 13.68 0.6 78.9*** 0.07*** (0.01) 0.03** (0.01) 0.46*** (0.07) 0.27*** (0.07) 0.58*** (0.09) −0.004 (0.02) – – – – −7637 3.240 3.250 31.49 8.16 8.15 0.33 141*** t 0.09*** (0.01) 0.03** (0.01) 0.44*** (0.05) 0.28*** (0.05) 0.62*** (0.07) 0.015 (0.02) 7.64*** (0.85) – – −7537 3.198 3.209 31.39 10.86 10.94 0.60 106*** SKt N t SKt 0.06*** (0.01) 0.015 (0.01) 0.45*** (0.05) 0.29*** (0.05) 0.63*** (0.07) 0.010 (0.02) 8.32*** (0.97) −0.15*** 0.017 (0.01) 0.03*** (0.01) 0.60*** (0.14) 0.16*** (0.06) 0.65*** (0.10) −0.03 (0.03) – – – 0.004 (0.01) 0.02** (0.01) 0.69*** (0.14) 0.13*** (0.06) 0.74*** (0.08) −0.02 (0.01) 10.2*** (1.52) – 0.002 (0.01) 0.02** (0.01) 0.69*** (0.14) 0.13*** (0.06) 0.74*** (0.08) −0.02 (0.01) 10.2*** (1.52) −0.01 (0.02) −7510 3.187 3.199 33.9 9.85 10.08 0.5 47.3*** – −7709 3.350 3.359 16.66 14.19 14.27 0.29 77.3*** – −7658 3.328 3.339 18.63 14.01 13.48 0.37 55.5*** (0.02) −7658 3.328 3.341 18.91 14.03 13.47 0.38 58.7*** Panel b CAC40 Cst(M) AR (1) d ϕ1 ˇ1 Log(â)   ln(ℓ) AIC SIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) FTSE 100 S&P 500 N t SKt N t SKt N t SKt 0.05*** (0.01) −0.06*** (0.01) 0.64*** (0.09) 0.18*** (0.05) 0.67*** (0.06) −0.03 (0.02) – – – – −7758 3.319 3.329 19.61 15.68 14.94 0.85 128.25*** 0.05*** (0.01) −0.06*** (0.01) 0.59*** (0.06) 0.18*** (0.04) 0.70*** (0.04) −0.004 (0.01) 7.87*** (0.96) – – −7655 3.276 3.287 20.22 21.48 20.95 1.42 69.25*** 0.03*** (0.01) −0.07*** (0.01) 0.60*** (0.06) 0.19*** (0.04) 0.71*** (0.04) −0.007 (0.01) 8.30*** (1.03) −0.09*** (0.02) −7644 3.272 3.284 21.36 20.45 19.70 1.32 47.17*** 0.03** (0.01) −0.05*** (0.01) 0.59*** (0.06) 0.13*** (0.04) 0.64*** (0.05) −0.01 (0.02) – – – – −6517 2.760 2.770 27.98 20.78 21.01 0.96 98.88*** 0.04*** (0.01) −0.06*** (0.01) 0.58*** (0.06) 0.15*** (0.03) 0.65*** (0.15) −0.01 (0.01) 9.67*** (1.30) – – −6460 2.736 2.747 28.61 20.79 21.49 0.98 69.45*** 0.03** (0.01) −0.07*** (0.01) 0.58** (0.06) 0.15*** (0.03) 0.66*** (0.05) −0.01 (0.01) 10.02*** (1.43) −0.06*** (0.02) −6455 2.735 2.747 28.97 20.89 21.56 0.99 50.40*** 0.04*** (0.01) 0.001 (0.01) 0.42*** (0.08) 0.16*** (0.06) 0.56*** (0.11) 0.008 (0.03) – – – – −6165 2.615 2.625 34.43 12.27 13.01 0.75 155.83*** 0.05*** (0.01) −0.012 (0.01) 0.42*** (0.06) 0.19*** (0.04) 0.61*** (0.06) 0.04 (0.03) 6.95*** (0.73) – – −6066 2.574 2.585 37.49 14.09 14.80 0.94 79.18*** 0.04*** (0.01) −0.02* (0.01) 0.43*** (0.06) 0.19*** (0.05) 0.61*** (0.06) 0.03 (0.03) 7.21*** (0.77) −0.06*** (0.01) −6062 2.572 2.584 38.76 13.88 14.60 0.90 64.0*** Notes: ln(ℓ) is the value of the maximized log-likelihood. AIC is the Akaike (1974) Information Criterion and SIC is the Schwarz Information Criterion. Q(20) and Q2 (20) are the Box–Pierce statistics for remaining serial correlation for respectively standardized and squared standardized residuals. RBD(20) is the residual based diagnostic for conditional heteroscedasticity, using 20 lags. The ARCH(10) is LM-ARCH test of Engle (1982), using 10 lags. P(60) is the Pearson goodness-of-fit statistic for 60 cells. Figures between parentheses are the standard errors. N, t and SKt are respectively normal, Student-t and the skewed Student-t distribution. * Significance level at 10%. ** Significance level at 5%. *** Significance level at 1%. S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Log(â) DOW JONES N Table 9 AR (1)-FIAPARCH (1,d,1) model estimation. Panel a Cst(M) AR (1) d ϕ1 ˇ1 1 DAX DOW JONES NASDAQ N t SKt N t SKt 0.03*** (0.01) 0.03** 0.06*** (0.01) 0.02** 0.04*** (0.01) 0.02** 0.02** (0.01) 0.02** 0.04*** (0.01) 0.02*** (0.01) 0.014 (0.01) 0.40*** 0.009 (0.01) 0.41*** (0.07) (0.07) (0.01) (0.01) (0.01) (0.01) 0.46*** (0.08) 0.19*** 0.58*** (0.08) 0.14*** 0.61*** (0.08) 0.14*** 0.41*** (0.09) 0.30*** (0.05) (0.03) (0.03) (0.05) 0.59*** (0.09) 0.42*** 0.68*** (0.06) 0.70*** 0.64*** (0.06) 0.31*** (0.07) 0.31*** 0.29*** (0.04 0.63*** (0.06) 0.72*** 0.65*** N 0.28*** (0.04 0.63*** (0.06) 0.04*** (0.01) 0.03** NIKKEI t SKt N t SKt 0.07*** (0.01) 0.03** 0.05*** (0.01) 0.03** −0.02 (0.01) −0.02 (0.01) 0.03*** −0.02 (0.01) 0.03*** (0.01) (0.01) 0.46*** (0.09) 0.22*** 0.46*** (0.09) 0.22*** (0.03) (0.03) 0.61*** (0.07) 0.55*** 0.61*** (0.07) 0.55*** (0.01) (0.01) (0.01) 0.38*** (0.05) 0.29*** 0.36*** (0.05) 0.30*** 0.37*** (0.05) 0.30*** (0.09) (0.07) (0.06) 0.53*** (0.01) 0.64*** 0.55*** (0.09) 0.38*** 0.42*** 0.56*** (0.08) 0.40*** 0.04*** (0.01) 0.43*** (0.08) 0.22*** (0.04 0.58*** (0.08) 0.56*** (0.07) (0.07) (0.15) (0.13) (0.13) (0.10) (0.08) (0.08) (0.11) (0.10) (0.10) 1.39*** (0.14) 1.43*** (0.11) 8.35*** 1.43*** (0.12) 8.66*** 1.58*** (0.15) 1.60*** (0.11) 8.66*** 1.64*** (0.11) 9.27*** 1.40*** (0.18) – – 1.57*** (0.13) 9.27*** 1.28*** (0.16)  1.59*** (0.13) 8.73*** 1.41*** (0.16) 11.9*** 1.41*** (0.16) 11.9*** (1.24) (1.36) (1.01) (1.06) (1.02) (1.15) (1.95) (1.95)  – – −6947 3.092 3.104 20.26 5.90 5.89 0.28 131.3*** ln(ℓ) A1C S1C Q(20) Q2 (20) RBD(20) ARCH(10) P(60) Panel b Cst(M) AR (1) d ϕ1 ˇ1 1 ı   ln(ℓ) AIC BIC Q(20) Q2 (20) RBD(20) ARCH(10) P(60) −0.11*** (0.02) −6844 3.047 3.062 21.92 6.08 4.2 0.3 69.25*** – – −6857 3.053 3.066 20.29 6.04 4.12 0.3 85.77*** – – – – −6051 2.559 2.570 21.22 20.60 20.89 1.34 98.5*** CAC40 – – −5974 2.527 2.540 22.47 18.62 18.33 1.14 70.6*** −0.08*** (0.01) −5966 2.525 2.538 22.85 10.93 18.14 1.12 47.8*** – – – – −7596 3.223 3.234 32.64 9.59 9.80 0.20 112*** – – −7510 3.187 3.199 31.44 8.89 5.10 0.21 96.1*** FTSE 100 −0.15*** (0.02) −7483 3.176 3.190 32.37 8.82 9.76 0.19 50.1*** – – – – −7643 3.321 3.332 20.97 19.02 18.08 0.67 63.8*** – – −7605 3.305 3.318 22.01 17.43 17.13 0.56 60.2*** −0.000* (0.02) −7605 3.306 3.320 22.02 17.43 17.12 0.56 61.5*** S&P 500 N t SKt N t SKt N t SKt 0.008 (0.01) −0.04*** (0.01) 0.36*** (0.06) 0.25*** (0.06) 0.51*** (0.01) 0.62*** (0.12) 1.46*** (0.11) – – – – −7689 3.290 3.301 21.02 13.73 13.15 0.81 105.89*** 0.03** (0.01) −0.06*** (0.01) 0.40*** (0.06) 0.25*** (0.03) 0.58*** (0.07) 0.57*** (0.10) 1.49*** (0.10) 8.89*** (1.18) – – −7612 3.258 3.271 22.11 13.62 13.21 0.78 54.89*** 0.01 (0.01) −0.06*** (0.01) 0.42*** (0.06) 0.26*** (0.03) 0.59*** (0.06) 0.56*** (0.10) 1.48*** (0.10) 9.28*** (1.24) −0.10*** (0.02) −7600 3.253 3.267 22.41 13.62 13.22 0.77 45.50*** 0.01 (0.01) −0.06*** (0.01) 0.59*** (0.11) 0.22*** (0.05) 0.73*** (0.08) 0.44*** (0.09) 1.40*** (0.17) – – – – −6478 2.744 2.755 26.67 18.58 18.58 0.69 86.13*** 0.02** (0.01) −0.06*** (0.01) 0.54*** (0.07) 0.23*** (0.03) 0.70*** (0.05) 0.49*** (0.08) 1.39*** (0.14) 10.4*** (1.54) – – −6422 2.721 2.733 26.96 18.78 19.33 0.75 58.31*** 0.01 (0.01) −0.06*** (0.01) 0.56*** (0.08) 0.23*** (0.03) 0.71*** (0.06) 0.50*** (0.08) 1.38*** (0.14) 10.5*** (1.62) −0.07*** (0.02) −6416 2.719 2.732 26.81 19.16 19.67 0.78 45.36 0.01* (0.01) 0.02* (0.01) 0.19*** (0.22) −0.08 (1.17) 0.06 (1.37) 0.85*** (0.20) 1.63*** (0.53) – – – – −6089 2.583 2.594 34.46 27.63 28.59 1.83 120.42*** 0.03*** (0.01) 0.0015 (0.01) 0.27*** (0.06) 0.18*** (0.09) 0.41*** (0.13) 0.78*** (0.15) 1.57*** (0.13) 8.06*** (0.98) – – −6015 2.552 2.564 36.00 17.53 18.40 1.12 48.49*** 0.02** (0.01) −0.004 (0.01) 0.28*** (0.05) 0.18*** (0.08) 0.43*** (0.12) 0.76*** (0.14) 1.57*** (0.12) 8.32*** (1.03) −0.07*** (0.01) −6007 2.549 2.563 36.49 17.19 18.01 1.09 76.56*** 315 Notes: ln(ℓ) is the value of the maximized log-likelihood. AIC is the Akaike (1974). Q(20) and Q2 (20) are the Box–Pierce statistics for remaining serial correlation for respectively standardized and squared standardized residuals. RBD(20) is the residual based diagnostic for conditional heteroscedasticity, using 20lags. The ARCH(10) is LM-ARCH test of Engle (1982), using 10 lags. P(60) is the Pearson goodness-of-fit statistic for 60 cells. Figures between parentheses are the standard errors. N, t and SKt are respectively normal, Student-t and the skewed Student-t distribution. * Significance level at 10%. ** Significance level at 5%. *** Significance level at 1%. S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 (0.11) ı 316 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Table 8 provides the estimation of another widely used model known to cope with long memory in financial time series: the HYGARCH model. It is basically a generalization of FIGARCH model. As shown above, the HYGARCH model nests a FIGARCH model when ˛ = 1. Thus, similar to FIGARCH (1,d,1), HYGARCH captures the long range dependence by the fractionary integrated parameter d. Evidence of long memory is proved since the d ranges between zero and one. This is confirmed in Table 8 where HYGARCH’s d parameter for each index series is within 0.42 and 0.69 interval. While FIGARCH and HYGARCH models are known to successfully deal with volatility clustering and long range memory in financial time series, they fail to take into account the asymmetry in returns volatility (e.g. Baillie et al., 1996, 2000; Bollerslev & Jubinski, 1999; Davidson, 2004). To capture this stylized fact, we model each of our index returns series using FIAPARCH model. Table 9 reports the FIAPARCH (1,d,1) model estimates results for the seven times series under the same three distributions (normal, Student-t and skewed Student-t). According to each of the model selection criterion, the FIAPARCH model outperforms all the alternative models (RiskMetrics, GARCH, FIGARCH and HYGARCH). Furthermore, under a skewed Student-t distribution, the FIAPARCH provides the best model for all our index returns series. As robustness checks we repeat the above analysis using others volatility models: the EGARCH, PGARCH, GARCH-M, GJR-GARCH, VGARCH, FIEGARCH, and also bilinearity models. For each volatility model, we run three specifications based on the three alternative error distributions: Normal, Student-t and skewed Student-t. Our untabulated results show that skewed Student-t AR (1)-FIAPARCH (1,d,1) outperforms all the above volatility models. Moreover, to see whether our results are sensitive to the choice of the mean equation, we again repeat the same analysis using AR (k), where k = 2, 3, 4, 5, 10, 20 and 30, and this for all the returns indices and for all the volatility models (including RiskMetrics, GARCH, FIGARCH and HYGARCH). Our unreported findings indicate that the skewed Student-t AR (1)-FIAPARCH (1,d,1) yet provides better fit than the remaining models regardless of the order of autocorrelation (k) in the mean equation.5 We therefore use the skewed Student-t AR (1)-FIAPARCH (1,d,1) to compute VaR estimates. We also consider the normal and Student-t distributions to see how sensitive our VaR estimates are to the error distribution assumption. We do so in the next section and this for short and long trading positions. 5.2. The VaR analysis: the in-sample and out-sample VaR estimation In this sub-section, we estimate the in-sample one-day-ahead VaR using AR (1)-FIAPARCH model under the three alternative innovation’s distributions (normal, Student-t and skewed Studentt) and this for each of the seven stock index returns. We first compute the failure rate for long and short position. The failure rate for the short trading position denotes the percentage of positive returns larger than the VaR prediction. However, for the long trading positions, the failure rate is the percentage of negative returns smaller than the VaR prediction. We also compute the Kupiec’s (1995) LR tests and the Dynamic Quantile (DQ) test. The VaR levels range (˛) from 0.05 to 0.01 for the short trading position and from 0.95 to 0.99 for the long trading positions. Table 10 provides the in-sample one-day-ahead VaR results using AR (1)-FIAPARCH model for each index series under the normal, Student-t and skewed Student-t distributions. We report the failure rate along with the Kupiec’s (1995) LR test and the Dynamic Quantile test and their corresponding P-values. The results clearly indicate that VaR model based on the normal AR (1)-FIAPARCH model fails to model large positive and negative returns. In fact, the hypothesis of model adequacy is strongly rejected as evidenced by the considerable difference between the prefixed level (˛) and the failure rate. This is expected given the excess kurtosis and skewness in our returns data, and in financial time series in general. So it is not surprising that the FIAPARCH provides better results when we employ Student-t. The accuracy of FIAPARCH is even higher when we consider skewed Student-t. In fact, it outperforms both the normal FIAPARCH and Student-t FIAPARCH in estimating VaR for short as well as long trading positions. While in-sample performance provides a good indication about a model forecasting accuracy, it is not a prerequisite for a good outof-sample performance (Hansen & Lunde, 2005; Pagan & Schwert, 1990). Accordingly, we provide out-of-sample evaluation of the FIAPARCH model. Table 11 reports the out-of-sample one-dayahead VaR results using AR (1)-FIAPARCH model, and this for short and long trading positions and under different error distribution assumptions. The out-of-sample VaR estimates are computed based on 1000 observations (i.e. last five years). We re-estimate the AR (1)-FIAPARCH model every 50 observations in the outof-sample period. The overall results are similar to those of the in-sample analysis. In fact, compared to normal and Student-t, the skewed Student-t FIAPARCH model provides the most accurate VaR estimates. However, unlike in-sample VaR results, the out-of-sample VaR under a normal distribution outperforms the symmetric Student-t FIAPARCH. This is because the Student-t distribution is relatively conservative. As stated above the Student-t can capture excess kurtosis but not excess skewness. In untabulated results, we re-estimate in-sample and out-ofsample VaR for short and long trading positions using RiskMetrics, GARCH (1,1), FIGARCH (1,d,1) as well as several others volatility models, in particular the EGARCH, PGARCH, GARCH-M, GJRGARCH, V-GARCH, FIEGARCH, and also bilinearity models. For each volatility model we run three specifications based on the three alternative error distributions: Normal, Student-t and skewed Student-t. Our results show that skewed Student-t AR (1)FIAPARCH (1,d,1) continues to outperform all the studied volatility models.6 We also find that RiskMetrics provides the least accurate VaR estimates. This is likely due to the failure of RiskMetrics to account for the main stylized facts of asset returns. We again repeat the same analysis using AR (k), where k = 2, 3, 4, 5, 10, 20 and 30, and this for all the returns indices and for all the volatility models. Our findings indicate that the skewed Student-t AR (1)-FIAPARCH (1,d,1) continues to provide the most accurate VaR estimates than the remaining models and this regardless of the order of autocorrelation (k) in the mean equation.7 It is noteworthy that the accuracy of VaR estimates is not sensitive to the mean process specification. To summarize, our findings provide strong and reliable evidence that FIAPARCH model under skewed Student-t distribution provides the most accurate VaR estimates. This can be explained by the fact that this model takes simultaneously into account the salient features of financial time series: fat tails, asymmetry, volatility clustering and long memory. Our findings, hence, corroborate the calls for the use of more realistic assumptions in 6 5 All untabultated results are available upon request. 7 The results are available upon request. The results are available upon request. S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 317 Table 10 In-sample VaR estimation results. Panel a CAC 40 Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.959 0.979 0.991 0.993 0.997 0.958 0.981 0.993 0.997 0.999 0.951 0.976 0.990 0.995 0.997 9.241 4.095 0.510 1.722 0.428 7.984 8.620 6.102 4.427 6.819 0.157 0.315 0.317 0.254 0.140 0.002 0.042 0.474 0.189 0.512 0.004 0.003 0.013 0.035 0.009 0.691 0.574 0.573 0.614 0.707 16.03 13.88 35.15 109.3 113.6 13.05 19.42 57.09 60.51 5.194 3.421 6.663 33.26 93.35 29.33 0.024 0.053 0.000 0.000 0.000 0.070 0.006 0.000 0.000 0.636 0.843 0.464 0.000 0.000 0.000 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.051 0.030 0.015 0.008 0.005 0.056 0.030 0.010 0.005 0.003 0.051 0.025 0.008 0.004 0.002 0.224 5.984 11.792 10.870 9.929 4.181 5.156 0.373 0.282 1.423 0.116 0.009 1.385 0.084 0.140 0.635 0.014 0.000 0.000 0.001 0.040 0.0231 0.541 0.595 0.232 0.733 0.921 0.239 0.771 0.707 5.094 10.28 22.72 19.52 27.74 7.027 10.16 4.899 6.884 3.023 2.914 3.121 4.955 8.273 0.390 0.648 0.172 0.001 0.006 0.000 0.425 0.179 0.672 0.440 0.882 0.892 0.873 0.665 0.309 0.999 Panel b DAX Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.960 0.981 0.993 0.995 0.997 0.959 0.983 0.995 0.998 0.998 0.950 0.976 0.992 0.996 0.998 10.571 8.079 5.709 0.574 0.005 8.325 15.306 14.611 10.535 4.393 0.039 0.517 4.206 1.471 1.857 0.001 0.004 0.016 0.448 0.941 0.003 0.000 0.000 0.001 0.036 0.842 0.471 0.040 0.225 0.172 13.56 12.16 8.567 11.54 40.16 13.30 16.42 16.61 30.94 87.25 3.280 2.461 6.663 14.55 60.34 0.059 0.095 0.285 0.116 0.000 0.065 0.021 0.020 0.000 0.000 0.857 0.929 0.464 0.042 0.000 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.054 0.031 0.015 0.008 0.0057 0.060 0.031 0.013 0.005 0.002 0.053 0.025 0.009 0.004 0.002 2.024 7.849 12.930 9.979 14.124 9.760 7.849 4.019 0.524 0.261 0.912 0.021 0.089 0.287 0.143 0.154 0.005 0.000 0.001 0.000 0.001 0.005 0.044 0.469 0.609 0.339 0.882 0.765 0.591 0.704 15.20 18.09 23.12 16.70 21.13 29.75 28.29 16.24 2.204 0.673 9.804 9.809 5.615 0.952 0.246 0.033 0.011 0.001 0.019 0.003 0.000 0.000 0.022 0.947 0.998 0.199 0.199 0.585 0.995 0.999 Panel c Dow Jones Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.9950 0.9975 0.956 0.979 0.988 0.995 0.997 0.954 0.980 0.994 0.998 0.999 0.947 0.976 0.990 0.996 0.998 4.088 3.432 0.905 0.019 0.374 1.773 6.508 10.446 11.980 12.579 0.773 0.355 0.038 3.671 2.322 0.043 0.063 0.341 0.889 0.540 0.182 0.010 0.001 0.000 0.000 0.379 0.550 0.844 0.055 0.127 7.305 7.668 5.660 7.632 27.13 6.007 11.96 12.06 9.388 8.269 3.961 5.154 2.848 15.60 2.262 0.397 0.362 0.579 0.366 0.000 0.538 0.101 0.098 0.225 0.309 0.784 0.641 0.898 0.029 0.943 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.048 0.027 0.014 0.009 0.007 0.053 0.025 0.011 0.007 0.004 0.049 0.023 0.009 0.006 0.003 0.145 0.786 9.549 17.934 29.684 1.020 0.185 1.5116 5.562 4.671 0.012 0.618 0.414 1.567 2.773 0.702 0.375 0.002 0.000 0.000 0.312 0.667 0.218 0.0183 0.030 0.909 0.431 0.519 0.210 0.095 9.039 3.828 19.48 29.39 49.87 13.78 1.409 5.102 8.653 6.478 11.42 2.700 2.492 3.040 4.293 0.249 0.799 0.006 0.000 0.000 0.055 0.985 0.647 0.278 0.485 0.121 0.911 0.927 0.881 0.745 Panel d FTSE 100 Short trading position Normal Studentt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.959 0.979 0.990 0.994 0.995 0.957 0.980 0.993 10.227 4.140 0.233 0.230 7.001 5.191 6.428 8.273 0.001 0.041 0.628 0.631 0.008 0.022 0.011 0.004 12.13 10.37 18.86 34.92 41.11 8.009 14.75 23.96 0.096 0.16 0.008 0.000 0.000 0.331 0.039 0.001 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.050 0.031 0.013 0.009 0.005 0.053 0.030 0.011 0.059 8.110 6.013 14.04 14.302 1.068 4.633 0.675 0.808 0.004 0.014 0.000 0.000 0.301 0.031 0.411 3.126 13.07 14.02 23.99 33.03 5.630 10.46 3.905 0.873 0.070 0.050 0.001 0.000 0.583 0.163 0.790 318 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Table 10 (Continued) Panel d FTSE 100 Short trading position skSt Long trading position Quantile Failure rate Kupiec LRT P-value 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.995 0.998 0.952 0.977 0.990 0.995 0.997 0.306 0.734 0.808 1.564 0.233 0.017 0.114 0.579 0.391 0.368 0.211 0.628 0.895 0.734 DQT 9.757 43.95 3.131 7.131 23.64 15.72 29.04 P-value Quantile Failure rate 0.202 0.000 0.872 0.415 0.001 0.027 0.000 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.005 0.003 0.050 0.024 0.009 0.003 0.002 Kupiec LRT 0.764 0.791 0.012 0.000 0.034 1.471 0.114 P-value 0.381 0.373 0.912 0.986 0.852 0.225 0.734 DQT 7.428 1.357 3.259 2.936 2.987 1.656 1.977 P-value 0.385 0.986 0.860 0.890 0.886 0.976 0.961 Panel e NASDAQ Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.962 0.981 0.992 0.996 0.997 0.961 0.983 0.994 0.998 0.999 0.950 0.973 0.991 0.995 0.997 16.881 7.952 4.119 2.768 0.000 14.024 14.095 14.031 11.881 12.512 0.016 0.218 0.596 0.296 0.288 0.000 0.004 0.042 0.096 0.814 0.000 0.000 0.000 0.000 0.000 0.898 0.640 0.439 0.585 0.590 20.90 20.85 8.329 7.933 1.250 19.61 25.33 15.96 9.109 8.196 5.320 8.582 9.358 2.838 0.510 0.003 0.003 0.304 0.338 0.989 0.006 0.000 0.025 0.244 0.315 0.620 0.284 0.227 0.899 0.999 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.054 0.031 0.015 0.012 0.009 0.059 0.032 0.014 0.009 0.005 0.050 0.023 0.011 0.006 0.003 2.117 7.274 14.054 41.385 51.664 7.850 9.781 8.166 12.89 9.719 0.005 0.562 1.571 1.161 1.351 0.145 0.006 0.000 0.000 0.000 0.005 0.001 0.004 0.000 0.001 0.941 0.453 0.210 0.281 0.245 9.500 17.64 21.50 73.23 96.40 17.54 27.02 14.16 23.31 18.40 7.648 9.492 9.132 4.097 3.517 0.218 0.013 0.003 0.000 0.000 0.014 0.000 0.048 0.001 0.010 0.364 0.219 0.243 0.768 0.833 Panel f Nikkei 225 Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.9950 0.9975 0.954 0.975 0.988 0.990 0.994 0.952 0.977 0.989 0.993 0.996 0.952 0.977 0.989 0.993 0.996 1.758 0.157 1.646 12.604 11.825 0.829 1.148 0.080 1.006 1.558 0.709 0.949 0.080 1.006 1.558 0.184 0.691 0.199 0.385 0.584 0.362 0.283 0.776 0.315 0.211 0.399 0.329 0.776 0.315 0.211 4.398 8.605 13.02 33.68 29.38 5.348 11.97 15.20 6.886 4.942 4.652 11.37 15.20 6.886 4.943 0.732 0.282 0.071 0.000 0.000 0.617 0.101 0.033 0.440 0.667 0.702 0.122 0.033 0.440 0.666 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.049 0.025 0.011 0.006 0.003 0.050 0.024 0.008 0.003 0.001 0.050 0.024 0.008 0.003 0.001 0.086 0.070 0.740 1.434 2.279 0.031 0.090 0.845 1.196 2.068 0.031 0.090 1.156 1.196 2.068 0.768 0.790 0.389 0.231 0.131 0.858 0.763 0.357 0.274 0.150 0.858 0.763 0.282 0.274 0.150 2.319 3.454 3.708 7.857 3.068 6.044 2.909 4.889 1.470 3.119 6.044 2.908 4.997 1.470 3.120 0.940 0.840 0.812 0.345 0.878 0.534 0.893 0.673 0.983 0.873 0.534 0.893 0.660 0.983 0.873 Panel g S&P 500 Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.958 0.977 0.990 0.995 0.997 0.953 0.980 0.994 0.997 0.999 0.947 0.974 0.991 0.997 0.999 7.554 1.295 0.031 0.299 0.003 1.319 5.851 10.325 10.066 12.521 0.440 0.034 1.940 5.720 6.958 0.005 0.255 0.86 0.584 0.953 0.250 0.015 0.001 0.001 0.000 0.507 0.852 0.163 0.016 0.008 6.848 8.668 6.774 31.68 29.32 4.843 9.895 28.09 24.21 5.388 9.631 7.823 11.67 15.46 68.81 0.444 0.277 0.452 0.000 0.000 0.679 0.194 0.000 0.001 0.612 0.210 0.348 0.111 0.030 0.000 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.051 0.031 0.017 0.011 0.007 0.058 0.032 0.013 0.007 0.003 0.054 0.029 0.010 0.005 0.003 0.357 8.2082 22.373 27.143 34.304 6.456 9.751 5.435 4.814 2.810 2.098 3.300 0.164 0.777 1.347 0.550 0.004 0.000 0.000 0.000 0.011 0.001 0.019 0.028 0.093 0.147 0.069 0.684 0.377 0.245 11.37 14.66 24.20 23.95 45.37 13.14 14.61 8.605 8.679 25.05 9.166 11.35 4.176 7.140 26.32 0.123 0.040 0.001 0.001 0.000 0.068 0.041 0.282 0.276 0.000 0.240 0.124 0.759 0.414 0.000 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 319 Table 11 Out-of-sample VaR estimation results. Panel a CAC 40 Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.963 0.987 0.997 0.999 0.999 0.955 0.982 0.995 0.998 0.999 0.965 0.987 0.993 0.998 0.998 3.895 7.145 6.825 4.797 1.169 0.543 2.224 3.093 2.343 1.169 5.268 7.145 1.015 2.343 0.107 0.048 0.007 0.008 0.028 0.279 0.460 0.135 0.078 0.125 0.279 0.021 0.007 0.313 0.125 0.742 7.072 10.31 5.285 3.313 1.091 7.531 6.375 2.803 1.871 1.103 9.717 10.00 2.372 1.823 0.128 0.421 0.171 0.625 0.854 0.993 0.375 0.496 0.902 0.966 0.992 0.205 0.188 0.936 0.968 0.999 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.066 0.038 0.019 0.010 0.007 0.059 0.032 0.013 0.008 0.004 0.066 0.040 0.023 0.017 0.013 4.918 5.996 6.472 3.888 5.435 1.616 1.849 0.830 1.529 0.762 4.918 7.832 12.485 17.754 21.976 0.026 0.014 0.010 0.048 0.0197 0.203 0.173 0.362 0.216 0.382 0.026 0.005 0.000 0.000 0.000 18.23 21.98 18.97 20.85 33.29 12.79 14.09 11.29 16.30 3.132 15.16 29.45 33.65 52.35 88.70 0.010 0.002 0.008 0.003 0.000 0.077 0.049 0.126 0.022 0.872 0.033 0.000 0.000 0.000 0.000 Panel b DAX Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.968 0.988 0.998 0.999 0.999 0.968 0.990 0.999 0.999 1.000 0.965 0.987 0.998 0.999 1.000 7.776 8.557 9.626 4.797 1.169 7.776 11.904 13.476 4.797 NaN 5.268 7.145 9.626 4.797 NaN 0.005 0.003 0.001 0.028 0.279 0.005 0.000 0.000 0.028 1.000 0.021 0.007 0.001 0.028 1.000 10.54 7.470 6.694 43.21 80.70 10.64 10.21 28.28 43.21 2.506 10.21 6.448 6.694 43.21 2.506 0.159 0.381 0.461 0.000 0.000 0.154 0.176 0.000 0.000 0.926 0.176 0.488 0.461 0.000 0.926 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.057 0.031 0.021 0.014 0.008 0.060 0.030 0.019 0.008 0.004 0.056 0.029 0.014 0.006 0.004 0.988 1.373 9.284 10.911 7.640 1.984 0.964 6.472 1.529 0.762 0.730 0.624 1.437 0.188 0.762 0.320 0.241 0.002 0.000 0.005 0.158 0.325 0.010 0.216 0.382 0.392 0.429 0.230 0.663 0.382 8.071 12.93 41.59 60.19 58.26 8.375 12.85 38.91 25.03 6.793 7.345 11.62 23.84 3.366 6.889 0.326 0.073 0.000 0.000 0.000 0.300 0.075 0.000 0.000 0.450 0.393 0.113 0.001 0.849 0.440 Panel c Dow Jones Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.9950 0.9975 0.961 0.986 0.992 0.996 0.999 0.958 0.988 0.995 0.999 1.000 0.954 0.985 0.992 0.999 0.999 2.746 5.888 0.433 0.215 1.169 1.421 8.557 3.093 4.797 NaN 0.345 4.777 0.433 4.797 1.169 0.097 0.015 0.510 0.642 0.279 0.233 0.003 0.078 0.028 1.000 0.556 0.028 0.510 0.028 0.279 7.206 7.426 12.32 0.289 1.046 6.506 9.757 2.592 3.286 2.506 6.103 7.905 12.27 3.287 1.044 0.407 0.385 0.090 0.999 0.994 0.481 0.202 0.919 0.857 0.926 0.527 0.341 0.091 0.857 0.994 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.061 0.036 0.026 0.016 0.009 0.063 0.033 0.017 0.009 0.003 0.061 0.03 0.013 0.009 0.002 2.387 4.378 17.947 15.343 10.099 3.298 2.389 4.091 2.596 0.094 2.387 0.964 0.830 2.596 0.107 0.122 0.036 0.000 0.000 0.001 0.069 0.122 0.043 0.107 0.758 0.122 0.325 0.362 0.107 0.742 17.39 24.76 53.59 36.21 20.74 24.17 24.92 24.48 5.586 2.326 22.22 17.81 2.480 5.740 0.729 0.015 0.000 0.000 0.000 0.004 0.001 0.000 0.000 0.588 0.939 0.002 0.012 0.928 0.570 0.998 Panel d FTSE 100 Short trading position Normal Student-t Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.968 0.988 0.998 0.999 0.999 0.968 0.990 0.999 0.999 7.776 8.557 9.626 4.797 1.169 7.776 11.904 13.476 4.797 0.005 0.003 0.001 0.028 0.279 0.005 0.000 0.000 0.028 10.54 7.470 6.694 43.21 80.70 10.64 10.21 28.28 43.21 0.159 0.381 0.461 0.000 0.000 0.154 0.176 0.000 0.000 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.057 0.031 0.021 0.014 0.008 0.060 0.030 0.019 0.008 0.988 1.373 9.284 10.911 7.640 1.984 0.964 6.472 1.529 0.320 0.241 0.002 0.000 0.005 0.158 0.325 0.010 0.216 8.071 12.93 41.59 60.19 58.26 8.375 12.85 38.91 25.03 0.326 0.073 0.000 0.000 0.000 0.300 0.075 0.000 0.000 320 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 Table 11 (Continued) Panel d FTSE 100 Short trading position skSt Quantile Failure rate 0.9975 0.95 0.975 0.99 0.995 0.9975 1.000 0.965 0.987 0.998 0.999 1.000 Long trading position Kupiec LRT NaN 5.268 7.145 9.626 4.797 NaN P-value DQT P-value Quantile Failure rate 1.000 0.021 0.007 0.001 0.028 1.000 2.506 10.21 6.448 6.694 43.21 2.506 0.926 0.176 0.488 0.461 0.000 0.926 0.0025 0.05 0.025 0.01 0.005 0.0025 0.004 0.056 0.029 0.014 0.006 0.004 Kupiec LRT 0.762 0.730 0.624 1.437 0.188 0.762 P-value DQT P-value 0.382 0.392 0.429 0.230 0.663 0.382 6.793 7.345 11.62 23.84 3.366 6.889 0.450 0.393 0.113 0.001 0.849 0.440 Panel e NASDAQ Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.971 0.983 0.993 0.995 0.997 0.968 0.985 0.994 0.997 0.999 0.951 0.977 0.990 0.994 0.997 10.867 2.952 1.015 0.000 0.094 7.776 4.777 1.886 0.939 1.169 0.021 0.168 0.000 0.188 0.094 0.000 0.085 0.313 1.000 0.758 0.005 0.028 0.169 0.332 0.279 0.884 0.681 1.000 0.663 0.758 11.32 3.545 1.017 0.416 1.465 9.606 4.663 1.786 1.590 3.104 7.655 2.601 0.420 0.523 1.608 0.125 0.830 0.994 0.999 0.983 0.212 0.700 0.970 0.979 0.875 0.363 0.919 0.999 0.999 0.978 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.057 0.030 0.016 0.015 0.010 0.070 0.033 0.015 0.009 0.006 0.055 0.023 0.014 0.006 0.003 0.988 0.964 3.076 13.059 12.782 7.5302 2.389 2.189 2.596 3.517 0.510 0.168 1.437 0.188 0.094 0.320 0.325 0.079 0.000 0.000 0.006 0.122 0.138 0.107 0.060 0.474 0.681 0.230 0.663 0.758 2.349 13.34 28.39 72.30 60.84 10.57 13.05 28.38 12.30 5.832 3.360 14.81 28.54 0.661 0.299 0.938 0.064 0.000 0.000 0.000 0.158 0.070 0.000 0.090 0.559 0.849 0.038 0.000 0.998 0.999 Panel f Nikkei 225 Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.9950 0.9975 0.955 0.980 0.993 0.996 0.998 0.948 0.980 0.995 0.997 0.999 0.949 0.981 0.995 0.998 0.999 0.543 1.099 1.015 0.215 0.107 0.0831 1.099 3.093 0.939 1.169 0.020 1.608 3.093 2.343 1.169 0.460 0.294 0.313 0.642 0.742 0.773 0.294 0.078 0.332 0.279 0.884 0.204 0.078 0.125 0.279 4.385 3.938 4.091 2.795 2.282 7.297 4.586 4.237 2.773 1.660 6.611 4.717 4.222 2.883 1.665 0.734 0.786 0.769 0.903 0.942 0.398 0.710 0.752 0.905 0.976 0.470 0.694 0.753 0.895 0.976 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.050 0.025 0.010 0.005 0.0025 0.043 0.022 0.014 0.006 0.003 0.048 0.023 0.009 0.003 0.001 0.048 0.024 0.010 0.003 0.001 1.080 0.384 1.437 0.188 0.094 0.085 0.168 0.104 0.939 1.169 0.085 0.041 0.000 0.939 1.169 0.298 0.535 0.230 0.663 0.758 0.770 0.681 0.746 0.332 0.279 0.770 0.838 1.000 0.332 0.279 11.56 3.960 8.344 1.318 7.076 13.63 3.050 11.26 3.955 1.619 13.63 2.750 9.692 3.994 1.614 0.115 0.784 0.303 0.987 0.421 0.058 0.880 0.127 0.784 0.977 0.058 0.907 0.206 0.780 0.978 Panel g S&P 500 Short trading position Normal Student-t skSt Long trading position Quantile Failure rate Kupiec LRT P-value DQT P-value Quantile Failure rate Kupiec LRT P-value DQT P-value 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.95 0.975 0.99 0.995 0.9975 0.965 0.986 0.994 0.998 0.999 0.961 0.986 0.997 0.999 1.000 0.954 0.985 0.996 0.999 1.000 5.268 5.888 1.886 2.343 1.169 2.746 5.888 6.825 4.797 NaN 0.345 4.777 4.706 4.797 NaN 0.021 0.015 0.169 0.125 0.279 0.097 0.015 0.008 0.028 1.000 0.556 0.028 0.030 0.028 1.000 8.170 7.684 1.882 1.882 0.904 9.293 7.714 4.992 3.222 2.506 7.969 6.584 3.838 3.222 2.506 0.317 0.361 0.966 0.966 0.996 0.232 0.358 0.660 0.863 0.926 0.335 0.473 0.798 0.863 0.926 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.05 0.025 0.01 0.005 0.0025 0.063 0.036 0.021 0.014 0.006 0.066 0.035 0.013 0.007 0.003 0.065 0.031 0.011 0.006 0.003 3.298 4.378 9.284 10.911 3.517 4.918 3.656 0.830 0.714 0.941 4.345 1.373 0.097 0.188 0.094 0.069 0.036 0.002 0.000 0.060 0.026 0.055 0.362 0.397 0.758 0.037 0.241 0.754 0.663 0.758 26.11 44.34 27.69 65.36 7.993 32.56 40.96 7.257 2.620 1.861 31.37 21.97 0.947 1.693 1.966 0.000 0.000 0.000 0.000 0.333 0.000 0.000 0.402 0.917 0.967 0.000 0.002 0.995 0.974 0.961 S. Mabrouk, S. Saadi / The Quarterly Review of Economics and Finance 52 (2012) 305–321 financial modeling (e.g. Roldán, 2009; Stiglitz, 2010; Willett, 2009). In the context of VaR, our results suggest that the use of realistic assumptions can help investors and risk managers further reduce the uncertainty associated with the maximum loss to incur. 6. Conclusion We estimate the one-day-ahead VaR for short and long trading position and this for seven stock indices (Dow Jones, Nasdaq100, S&P 500, DAX30, CAC40, FTSE100 and Nikkei 225). Since volatility is a key input to estimate VaR, the use of volatility models that take into account the properties of asset returns is crucial for the accuracy of VaR estimation. Therefore we carry out a thorough analysis in order to choose the appropriate volatility model. Because all returns series exhibit volatility clustering and long range memory, we examine several GARCH-type models including fractionary integrated models. Moreover, and with the exception of RiskMetrics which can only be assed under the normal distribution, we estimate each model under three alternative distributions: Normal, Student-t and skewed Student-t. Consistent with the idea that the accuracy of VaR estimates is sensitive to the adequacy of the volatility model used, we find that AR (1)-FIAPARCH (1,d,1) model, under a skewed Student-t distribution, outperforms all the models that we have considered including widely used ones such as GARCH (1,1) or HYGARCH (1,d,1). The superior performance of the skewed Student-t FIAPARCH model holds for all stock market indices, and for both long and short trading positions. Our findings can be explained by the fact that the skewed Student-t FIAPARCH model can jointly accounts for the salient features of financial time series: fat tails, asymmetry, volatility clustering and long memory. 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