Price Volatility in Maize Futures of Major Exporters

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University of the Witwatersrand, Johannesburg
Futures markets provide a platform for risk management and price discovery. Significant structural changes have taken place in futures markets over the last two decades transforming them into a volatile and fast paced trading environment, with heightened volatility expected to continue. Increased volatility in grain futures markets is of special concern to farmers, traders, academics, and policy makers as it impacts food security, renewable energy and the regulation of futures exchanges. Price volatility is investigated for maize futures listed in South Africa on the South African Futures Exchange (SAFEX), in the United States on the Chicago Board of Trade, in Argentina on the Mercado a Termino de Beunes Aires and in Brazil on the Brazilian Mercantile and Futures Exchange. A particular focus is placed on South African white maize futures, given its liquidity on SAFEX, its uniqueness as the only listed white maize contract traded on a futures exchange globally, and the importance of white maize as South Africa’s largest produced field crop and main staple food. This thesis investigates the effectiveness of price limits which are found to be ineffective in curbing volatility, and instead found to accelerate prices towards their limits prematurely, exacerbate volatility and impair market liquidity. The impact of sentiment as measured through volatility indices is also studied using a time-varying vector autoregressive framework. The results confirm the influence of sentiment on trading behaviour in white maize futures, and subsequently on price volatility. The level of speculative activity and its impact on price volatility is also examined using Granger-causality, variance decomposition and impulse response functions. Finally, volatility spillovers among key major exporters of maize is investigated using four multivariate GARCH models and a DCC-GARCH Connectedness approach, with the results confirm significant own and cross volatility spillovers and time-varying interdependence. This thesis makes novel contributions to the field of futures risk management. The work covered in this thesis is among the first to investigate price limits on SAFEX, the first to include SAVI White Maize in an empirical analysis, the first to quantify the level of speculative activity in the white maize futures market and the first to investigate spillover and dynamic connectedness in maize futures among key maize exporters
A thesis submitted to the Faculty of Commerce, Law and Management, University of the Witwatersrand in fulfillment of the requirements for the degree of Doctor of Philosophy in Finance. Johannesburg, South Africa, 2023
Price volatility, Futures, White maize, Speculation, Price limits, Dynamic connectedness, Volatility spillove, UCTD
Sayed, Ayesha. (2023). Price Volatility in Maize Futures of Major Exporters [PhD thesis, University of the Witwatersrand, Johannesburg]. WireDSpace.