Testing for intrinsic multifractality in the global grain spot market indices: A multifractal detrended fluctuation analysis

TL;DR

This study applies multifractal fluctuation analysis to global grain market indices, revealing complex multifractal behaviors and differences among various grains, which enhances understanding of price dynamics in these vital markets.

Contribution

It introduces the use of MF-DFA to analyze intrinsic multifractality in global grain indices, providing new insights and contrasting results with previous MF-DMA analysis.

Findings

Intrinsic multifractality confirmed in maize and barley.

Wheat and rice lack intrinsic multifractality.

Mixed results for GOI and soybeans highlight market complexity.

Abstract

Grains account for more than 50% of the calories consumed by people worldwide, and military conflicts, pandemics, climate change, and soaring grain prices all have vital impacts on food security. However, the complex price behavior of the global grain spot markets has not been well understood. A recent study performed multifractal moving average analysis (MF-DMA) of the Grains & Oilseeds Index (GOI) and its sub-indices of wheat, maize, soyabeans, rice, and barley and found that only the maize and barley sub-indices exhibit an intrinsic multifractal nature with convincing evidence. Here, we utilize multifractal fluctuation analysis (MF-DFA) to investigate the same problem. Extensive statistical tests confirm the presence of intrinsic multifractality in the maize and barley sub-indices and the absence of intrinsic multifractality in the wheat and rice sub-indices. Different from the MF-DMA results, the MF-DFA results suggest that there is also intrinsic multifractality in the GOI and soyabeans sub-indices. Our comparative analysis does not provide conclusive information about the GOI and soyabeans and highlights the high complexity of the global grain spot markets.