Are there asymmetric relations between real interest rates and agricultural commodity prices? Testing for threshold effects of US real interest rates and adjusted wheat, corn, and soybean prices

This article analyzes whether there are asymmetric relations between real interest rates and agricultural commodity prices using quarterly data of US interest rates and agricultural commodity prices over the period of 1983q1–2014q4. While the literature has identified statistically significant negative relations between real interest rates and agricultural commodity prices, this article extends the analysis by testing for threshold effects using Hansen’s (J Econom 93(2):345–368. https://doi.org/10.1016/S0304-4076(99)00025-1, 1999) fixed-effect panel threshold model and testing procedure. The empirical results indicate that real interest rates and agricultural commodity prices follow a U-shaped relationship, with − 1.45 being the turning point from negative to positive effects. Specifically, if real interest rates below the threshold of − 1.45 are increased by 1%, agricultural commodity prices will decrease by 8.1%, and if real interest rates are equal or above − 1.45 and are increased by 1%, agricultural commodity prices will increase by 3.4%. As the literature suggests an inverse proportional relation between real interest rates and agricultural commodity prices, a theoretical explanation for this phenomenon has yet to be found but is probably related to assumptions about market participants’ expectations and risk behavior.