Hayet SOLTANI

Dr. Hayet SOLTANI


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 September 2024 in EuroMed Journal of Business
Verified
Journal Article
Closed access
HSHayet SOLTANI
Hayet SOLTANI
JTJamila Taleb
Jamila Taleb
FHFatma Ben Hamadou
Fatma Ben Hamadou
AMAbbes Mouna
Abbes Mouna
Purpose: This study investigates clean energy, commodities, green bonds and environmental, social and governance (ESG) index prices forecasting and assesses the predictive performance of various factors on these asset prices, used for the development of a robust forecasting support decision model using machine learning (ML) techniques. More specifically, we explore the impact of the financial stress on forecasting price. Design/methodology/approach: We utilize feature selection techniques to evaluate the predictive efficacy of various factors on asset prices. Moreover, we have developed a forecasting model for these asset prices by assessing the accuracy of two ML models: specifically, the deep learning long short-term memory (LSTM) neural networks and the extreme gradient boosting (XGBoost) model. To check the robustness of the study results, the authors referred to bootstrap linear regression as an alternative traditional method for forecasting green asset prices. Findings: The results highlight the significance of financial stress in enhancing price forecast accuracy, with the financial stress index (FSI) and panic index (PI) emerging as primary determinants. In terms of the forecasting model's accuracy, our analysis reveals that the LSTM outperformed the XGBoost model, establishing itself as the most efficient algorithm among the two tested. Practical implications: This research enhances comprehension, which is valuable for both investors and policymakers seeking improved price forecasting through the utilization of a predictive model. Originality/value: To the authors' best knowledge, this marks the inaugural attempt to construct a multivariate forecasting model. Indeed, the development of a robust forecasting model utilizing ML techniques provides practical value as a decision support tool for shaping investment strategies.

24 May 2023 in European Journal of Management and Business Economics
Verified
Journal Article
Open access
PDF file
HSHayet SOLTANI
Hayet SOLTANI
JTJamila Taleb
Jamila Taleb
MAMouna Boujelbène Abbes
Mouna Boujelbène Abbes
Purpose: This paper aims to analyze the connectedness between Gulf Cooperation Council (GCC) stock market index and cryptocurrencies. It investigates the relevant impact of RavenPack COVID sentiment on the dynamic of stock market indices and conventional cryptocurrencies as well as their Islamic counterparts during the onset of the COVID-19 crisis.Design/methodology/approach: The authors rely on the methodology of Diebold and Yilmaz (2012, 2014) to construct network-associated measures. Then, the wavelet coherence model was applied to explore co-movements between GCC stock markets, cryptocurrencies and RavenPack COVID sentiment. As a robustness check, the authors used the time-frequency connectedness developed by Barunik and Krehlik (2018) to verify the direction and scale connectedness among these markets.Findings: The results illustrate the effect of COVID-19 on all cryptocurrency markets. The time variations of stock returns display stylized fact tails and volatility clustering for all return series. This stressful period increased investor pessimism and fears and generated negative emotions. The findings also highlight a high spillover of shocks between RavenPack COVID sentiment, Islamic and conventional stock return indices and cryptocurrencies. In addition, we find that RavenPack COVID sentiment is the main net transmitter of shocks for all conventional market indices and that most Islamic indices and cryptocurrencies are net receivers.Practical implications: This study provides two main types of implications: On the one hand, it helps fund managers adjust the risk exposure of their portfolio by including stocks that significantly respond to COVID-19 sentiment and those that do not. On the other hand, the volatility mechanism and investor sentiment can be interesting for investors as it allows them to consider the dynamics of each market and thus optimize the asset portfolio allocation.Originality/value: This finding suggests that the RavenPack COVID sentiment is a net transmitter of shocks. It is considered a prominent channel of shock spillovers during the health crisis, which confirms the behavioral contagion. This study also identifies the contribution of particular interest to fund managers and investors. In fact, it helps them design their portfolio strategy accordingly.

9 December 2025 in Sustainable Development
Verified
Journal Article
Open access
BBBrahim Bergougui
Brahim Bergougui
BDBuhari Doğan
Buhari Doğan
ECEmmanuel Yamoah Cobbold
Emmanuel Yamoah Cobbold
HSHayet SOLTANI
Hayet SOLTANI
HSHAMID GHAZI SULIMANY
HAMID GHAZI SULIMANY
EEEhab Ebrahim Mohamed Ebrahim
Ehab Ebrahim Mohamed Ebrahim
This study examines the asymmetric effects of eco‐innovation on income‐based carbon emissions inequality within G7 economies over the period 1990–2023. Theoretically grounded in innovation diffusion theory and political economy frameworks, we argue that green technological advancements exert non‐linear, directional effects on emissions inequality due to differential adoption patterns across income groups, elite capture mechanisms, and path‐dependent lock‐in effects. Unlike prior research that conflates eco‐innovation types or focuses solely on aggregate emissions, we distinguish between comprehensive eco‐innovation ( ECON ) and process‐oriented eco‐innovation ( ECOP ), examining their separate positive and negative shocks on emissions inequality—measured as per capita CO 2 emissions of the wealthiest 10% of the population. Employing the method of moments quantile regression (MMQR) with asymmetric specifications, we provide novel evidence that increases and decreases in eco‐innovation produce differential distributional impacts across the emissions inequality spectrum. Our findings reveal that while eco‐innovation expansion reduces emissions inequality in low‐inequality contexts, its benefits are asymmetrically concentrated among affluent groups in high‐inequality settings, with process eco‐innovation showing heterogeneous effects across quantiles and innovation directions. These results underscore the critical need for differentiated policy interventions that ensure green technological transitions promote both environmental sustainability and social equity, preventing the entrenchment of carbon privilege among wealthy populations.

24 October 2025 in Sustainable Development
Verified
Journal Article
Closed access
Sunil TiwariSunil Tiwari
Sunil Tiwari
PTPanayiotis Tzeremes
Panayiotis Tzeremes
EKEmad Kazemzadeh
Emad Kazemzadeh
HSHayet SOLTANI
Hayet SOLTANI
BDBuhari Doğan
Buhari Doğan

12 August 2024 in Journal of the Knowledge Economy
Verified
Journal Article
Closed access
PDF file
HSHayet SOLTANI
Hayet SOLTANI
AMAbbes Mouna
Abbes Mouna

28 June 2022 in Asia-Pacific Journal of Business Administration
Verified
Journal Article
Closed access
HSHayet SOLTANI
Hayet SOLTANI
MAMouna Boujelbene Abbes
Mouna Boujelbene Abbes
Purpose: This study aims to investigate the impact of the COVID-19 pandemic on both of stock prices and investor's sentiment in China during the onset of the COVID-19 crisis.Design/methodology/approach: In this study, the ADCC-GARCH model was used to analyze the asymmetric volatility and the time-varying conditional correlation among the Chinese stock market, the investors' sentiment and its variation. The authors relied on Diebold and Yilmaz (2012, 2014) methodology to construct network-associated measures. Then, the wavelet coherence model was applied to explore the co-movements between these variables. To check the robustness of the study results, the authors referred to the RavenPack COVID sentiments and the Chinese VIX, as other measures of the investor's sentiment using daily data from December 2019 to December 2021.Findings: Using the ADCC-GARCH model, a strong co-movement was found between the investor's sentiment and the Shanghai index returns during the COVID-19 pandemic. The study results provide a significant peak of connectivity between the investor's sentiment and the Chinese stock market return during the 2015–2016 and the end of 2019–2020 turmoil periods. These periods coincide, respectively, with the 2015 Chinese economy recession and the COVID-19 pandemic outbreak. Furthermore, the wavelet coherence analysis confirms the ADCC results, which revealed that the used proxies of the investor's sentiment can detect the Chinese investors' behavior especially during the health crisis.Practical implications: This study provides two main types of implications: on the one hand, for investors since it helps them to understand the economic outlook and accordingly design their portfolio strategy and allocate decisions to optimize their portfolios. On the other hand, for portfolios managers, who should pay attention to the volatility spillovers between investor sentiment and the Chinese stock market to predict the financial market dynamics during crises periods and hedge their portfolios.Originality/value: This study attempted to examine the time-varying interactions between the investor's sentiment proxies and the stock market dynamics. Findings showed that the investor's sentiment is considered a prominent channel of shock spillovers during the COVID-19 crisis, which typically confirms the behavioral contagion theory.