Performance of systemic stress in agricultural commodities and its implication for volatility prediction in SSA equities

Abstract

Extensive research has underscored the linkage and risk exposure of Sub-Saharan Africa (SSA) equities to international agricultural commodities. However, the role of systemic agricultural commodity stress in predicting equity volatility has received less attention. We first utilize the Tail Event-driven NETwork (TENET) methodology to construct a Systemic Stress Index (SSI) for agricultural commodities to capture the extreme risks in these markets. We then develop a GARCH-MIDAS-SSI specification to examine the index's predictive capabilities and its relationship with SSA equities (Nigeria, Botswana, Uganda, Mauritius, Kenya, and Ghana). Our results show that the SSI significantly rises during global crises, and its upward trend correlates with increased volatility in SSA equities. More importantly, the SSI exhibits robust forecasting capabilities for volatility in SSA equity markets, both in-sample and out-of-sample. Given the deepening trend of commodity financialization and the frequent occurrence of global crises, these insights are pertinent for both investors and market regulators in their decision-making processes.