Chaker Aloui

One-day-ahead value-at-risk estimations with dual long-memory models: evidence from the Tunisian stock market

In this paper, we assess the one-day-ahead Value-at-Risk (VaR) performance for the Tunisian Stock Market (TSE). Using the ARFIMA-FIGARCH and ARFIMA-FIAPARCH models under three alternative innovation distributions: normal, Student and skewed Student, we show that the ARFIMA-FIAPARCH with skewed Student innovations outperforms the other models since it jointly considers the asymmetry, long-range memory and fat-tails in the TSE return behaviour. This model provides the better results for in and out-of-sample VaR estimations for both short and long trading positions.

Crude Oil Volatility Shocks and Stock Market Returns

Using two alternative approaches, this paper attempts to shed light on the volatility spillovers between crude oil markets and major stock markets. The first approach is based on the two-step technique suggested by Cheung and Ng (1996), and the second approach is founded on a multivariate generalized autoregressive conditional heteroskedasticity (GARCH)-type process. The empirical investigations were focused on West Texas Intermediate (WTI) and Brent crude oil cash prices and six major stock indexes, covering daily frequency data for the period 1989-2007. The findings indicate that oil price volatility has, in general, a negative impact on stock market behavior. Also, some asymmetry and persistence on oil price volatility have been detected. These results are consistent with those of previous empirical studies and have many practical implications for managing international portfolios and hedging risk on international equity and crude oil markets.

On the detection of extreme movements and persistent behaviour in Mediterranean stock markets: a wavelet-based approach

We combine the global Hurst exponent and Morlet wavelet multi-resolution analysis (MRA) to investigate the dynamic behaviour of six selected stock markets in the Mediterranean region. Specifically, we employ the resonance coefficients and their power spectra to identify potential extreme movements and long-term dependence in stock returns. Using weekly data for the period 2005 to 2010, our results reveal that the wavelet MRA is able to reconstruct the effects of major extreme shocks on stock returns of studied markets, such as the Asian financial crisis, the 9/11 terrorist attacks and the 2007–2009 financial crisis. Moreover, the wavelet-based global Hurst exponent indicates the presence of long-term dependencies in stock returns of all the considered markets, except for France where the anti-persistent behaviour is detected. Overall, our findings are useful to assess the stock market efficiency and provide new insights into stock market dynamics over different time scales.

Crude oil market efficiency: An empirical investigation via the Shannon entropy

This paper evaluates the time-varying degrees of weak-form efficiency of the crude oil markets using the Modified Shannon Entropy (MSE) and the Symbolic Time Series Analysis (STSA) approach. Using daily data from May 20, 1987 to March 6, 2012 for two worldwide crude oil benchmarks (West Texas Intermediate and Europe Brent), our findings reveal that the weak-form market efficiency of two oil markets evolves through time, but with different time trends. Moreover, the WTI market appears to be less efficient than the Europe Brent. These results have several implications for commodity portfolio hedgers and policymakers.

Financial Liberalization, Banking Crises and Economic Growth: The Case of South Mediterranean Countries

Abstract The central aim of this paper is to empirically assess the effects of financial liberalization on economic growth in the presence of banking crises. Our empirical investigation is based on a dynamic panel model for a sample of 10 South Mediterranean countries during the period 1980-2005. Results suggest that equity market liberalization positively affects economic growth in these countries, especially in the period of fragility and banking crises. Capital account liberalization, however, has no significant effects. As expected, banking crises exert negative effects on economic growth. When we control for the presence of macroeconomic stability and appropriate openness sequencing, the anticipated effects of capital account liberalization become significant. We conclude that macroeconomic reforms and trade opening are both crucial prerequisites for the success of the capital account liberalization process.

Information flow between stock return and trading volume: the Tunisian stock market

This paper investigates the dynamics of information flow between stock return and trading volume in the Tunisian Stock Market (TSE) using intraday data covering the year 2006. The Cross-Correlation Function (CCF) suggested by Cheung and Ng is employed to detect the causality in mean and in variance between stock return and trading volume. Our results reveal that contrary to the Mixture of Distribution Hypothesis (MDH), only a few Tunisian stocks display instantaneous correlations in mean and in variance between trading volume and stock return. However, strong evidence of lead-lag linkages in mean and in variance in major Tunisian stocks is found. This result supports the Sequential Information Arrival Hypothesis (SIAH) of Copeland (1976). Also, our results pointed out that the information flow in the TSE follows a sequential rather than simultaneous process indicating the rejection of the informational efficiency hypothesis.

Strength of co-movement between sector CDS indexes and relationship with major economic and financial variables over time and during investment horizons

ABSTRACT The main purpose of this article is to analyse the co-movement in both time and frequency between financial sector CDS indexes and between these indexes and their main economic and financial control variables for the period 2004–2014. Empirically, we implement the wavelet-squared coherence methodology to analyse the co-movement through time, frequency and power. Our results unveil that the co-movement between the three financial sectors’ CDSs changes through time and investment horizons, stressing the importance of hedging portfolios in real time. Also, we uncover that the changes in co-movement to relatively higher frequencies coincide with the inception of the recent global financial crisis. This result is collaborated with the co-movement between each CDS index and other global risk factors, including crude oil prices, interest rates and equity market volatility. Finally, we compare the wavelet coherence results with those of the DCC-FIAPARCH model and find that the two different approaches provide quite similar conditional correlations over time. Our results are important for investors, debtors, creditors and other decision-makers which are interested in CDS spread co-movements at different frequencies or investment horizons. It would be useful for all market participants to resort to an appropriate frequency domain to have better understanding of the sector CDS interrelationship behaviour in this domain.

Public and private information: Lessons from the emerging Tunisian stock market

The aim of the present research is to investigate the roles of public and private information flows in explaining intraday returns and intraday return volatility for a securities sample from the Tunisian stock market. Using an econometric approach based on uni-variate ARCH-type models, our empirical results reveal that in major Tunisian stocks the instantaneous private information proxied by the contemporaneous order imbalance is the dominant factor in explaining intraday returns. In addition, our findings cleary indicate that the trading volume represents a dominant factor to explain the intraday return volatility for the entirety of stocks when there is a simultaneous arrival of public and private information whether in the case of the instantaneous flow or in the sequential flow. Furthermore, our results indicate that volatility persistence disappears when trading volume and order imbalance are included as explanatory variables in the conditional variance equation.

GARCH-class models estimations and value-at-risk analysis for exchange rate

In this paper, we focus on three daily exchange rate returns dynamics. Indeed, we have assessed five GARCH-class models under three alternative distributions. Our findings confirm that the skewed Student-t FIAPARCH model performs very well. Then, we have computed short and long Value-at-Risk and Expected Shortfall based on AR (1) – FIAPARCH under normal, Student-t and skewed Student-t distributions. More precisely, we have investigated the estimation performance by computing both In-sample and Out-of-sample VaR for one-day-ahead horizon. Results reveal that VaR and ES estimations based on skewed Student-t FIAPARCH models outperform other models for both long and short trading positions.

A Multiple and Partial Wavelet Analysis of the Oil Price, Inflation, Exchange Rate, and Economic Growth Nexus in Saudi Arabia

ABSTRACT This article provides a fresh insight into the dynamic nexus between oil prices, the Saudi/US dollar exchange rate, inflation, and output growth rate in Saudi Arabia’ economy, using novel Morlet’ wavelet methods. Specifically, it implements various tools of methodology: the continuous wavelet power spectrum, the cross-wavelet power spectrum, the wavelet coherency, the multiple and the partial wavelet coherence to the annual sample period 1969–2014. Our results unveil that the relationships among the variables evolve through time and frequency. From the time-domain view, we show strong but non-homogenous linkages between the four variables. From the frequency-domain view, we uncover significant wavelet coherences and strong lead-lag relationships. From an economic view, the wavelet analysis shows that Saudi economy is still exposed to several global risk factors, which are mainly related to the oil market volatility, and the pegging of the local currency to the US dollar. Such risk factors strongly and negatively affect the real economic growth, exert more pressure on inflation, and substantially limit the freedom to pursue an independent monetary policy.