Zied Ftiti

Oil price and financial markets: Multivariate dynamic frequency analysis

The aim of this paper is to study the degree of interdependence between oil price and stock market index into two groups of countries: oil-importers and oil-exporters. To this end, we propose a new empirical methodology allowing a time-varying dynamic correlation measure between the stock market index and the oil price series. We use the frequency approach proposed by Priestley and Tong (1973), that is the evolutionary co-spectral analysis. This method allows us to distinguish between short-run and medium-run dependence. In order to complete our study by analysing long-run dependence, we use the cointegration procedure developed by Engle and Granger (1987). We find that interdependence between the oil price and the stock market is stronger in exporters׳ markets than in the importers׳ ones.

Uncertainty and the United States’ election effect on the economy: some thoughts and empirical illustrations

ABSTRACT This study discusses the general impact of Donald Trump’s election on the US and European economies as well as the effect of this political news on financial markets. To this end, we discuss different hypotheses from a theoretical view and empirically illustrate these thoughts when possible. Our analysis suggests that while the expected Trump measures might boost the US economy in the short term, these actions would have negative long-term consequences in the United States. Further, this new US policy will affect European economies and destabilize financial markets while increasing uncertainty, which could constrain growth and increase the downside risk.

Modelling the relationship between future energy intraday volatility and trading volume with wavelet

ABSTRACT Although the energy and stock markets are both characterized by volatility and liquidity, and there has been substantial research to explore the relationship between volatility and trading volume (TV) in stock markets, few researchers have investigated this relationship in energy markets. Moreover, studies that have explored this association within energy markets did not describe its nature or impetus. To redress this oversight, we investigate this relationship using intraday data from the oil and gas markets – the most liquid energy markets in the world. In this way, the current article extends the previous studies through the use of a frequency approach to propose an original analysis of the relationship between volume and volatility. More specifically, we employ a continuous wavelet transform to identify the lead–lag phase between volatility and volume. This framework supplants usual time series modelling, as it uses a measure of coherence for different frequencies and time-scales to capture further changes and time variation in the volume–volatility relationship. Our results provide supportive evidence for the well-known positive relationship between realized volatility and TV, thereby supporting the mixture distribution hypothesis. In particular, our results show that volume causes volatility only during ‘turbulent times’, while volatility causes volume during ‘good times’. Furthermore, there is no relationship between volume and volatility in the long term, due to the absence of noise traders and liquidity traders in the long run. These findings are helpful for investors and policymakers as they contribute to better forecast the TV and price volatility during turbulent and calm periods and over several investment horizons.

Modelling inflation shifts and persistence in Tunisia: perspectives from an evolutionary spectral approach

This article examines the dynamic characteristics of the inflation rate in Tunisia over the last two decades, and particularly following the onset of the Arab Spring in 2010 which causes distortions in this country’s monetary policy. We focus on the two specific dimensions of the Tunisian inflation rate: inflation regimes and persistence. We tackle this issue by adopting an evolutionary spectral approach, initially proposed by Priestley and Tong (1973). Our main findings indicate a stable inflation regime in the last 10 years, with an average inflation rate of around 5.5%. It is also found that the Tunisian inflation experienced a high degree of inertia which reflects its gradual responses to shocks. We also discuss the policy implications of these results, which typically require policy-makers to implement sound institutional reforms to reduce inflation.

Threshold effect in the relationship between investor sentiment and stock market returns: a PSTR specification

This article verifies whether the hypothesis of heterogeneous agent modelling and the behavioural heterogeneity framework can reproduce recent stylized facts regarding stock markets (e.g. the 1987 crash, internet bubble, and subprime crisis). To this end, we investigate the relationship between investor sentiment and stock market returns for the G7 countries from June 1987 to February 2014. We propose an empirical non-linear panel data specification based on the panel switching transition model to capture the investor sentiment-stock return relationship, while enabling investor sentiment to act asymmetrically, non-linearly, and time varyingly according to the market state and investor attitude towards risk. Our findings are twofold. First, we show that the hypotheses of efficiency, rationality, and representative agent do not hold in reproducing stock market dynamics. Second, investor sentiment affects stock returns significantly and non-linearly, but its effects vary with the market conditions. Indeed, the market appears predominated by fundamental investors in the first regime. In the second regime, investor sentiment effect is positively activated, increasing stock returns; however, when their overconfidence sentiment exceeds some threshold, this effect becomes inverse in the third regime for a high threshold level of market confidence and investor over-optimism.