The hotelling’s rule in practice analysis of gold mining sector

Abstract

The paper presented intends to fill up a gap in surveying the Hotelling Rule by taking a company based, microeconomic approach based on analyses of annual reports. Using selected data three fundamental hyphothesis are tested: 1) growth rate of margins (“net margins” including a capital charge) per unit realized by mining companies must exceed a rate equal to their cost of capital, 2) output shall follow deviations from the Hotelling growth line, 3) margins shall follow a path set by individually defined expected rate of return. The analysis was based on 5 leading gold producers, responsible for ca 15–20% of global primary production, all of them public and listed on a stock exchange for the entire period of 2004–2019/2020. As margin shall grow at a rate compensating individual risk of a company in consideration, they shall not be homogenous. At 1st step industry WACC was adopted to calculate a normalized capital charge. The calculations revealed no support for Hotelling Rule. There is no evidence that over a period of above 15 years margins follow any path determined by a growing expotential function, following a compound rate. Subsequently it was checked whether output volume is corrected due to development of actual versus expected (resulting from the Hotelling Rule) margin values. Selected companies were near indifferent to this parameter while taking decisions in area of volumes supplied. Neither there is no evidence of relation between changes in output and margins. Finally, it was checked whether differences between expected and actual margins’ growth paths could be described by a linear function, resulting from consequent adoption of a risk rate component. Here neither any evidence was found. In conclusion no support for the Hotelling rule was identified.