Regional differences in industry specialization in the sustainability assurance market

Purpose: This paper uses institutional theory to analyze the structure of the sustainability assurance market (SAM) at a global level. The purpose of this paper is to determine if regional differences affect industry specialization in this market. Design/methodology/approach: Using a sample of 3,657 sustainability reports (SRs) with assurance statements, the authors study the global and regional specialization of assurers by breaking down the sample into three main regions. The authors approach industry specialization using previous methodologies applied to the financial audit market, and explain differences statistically significant among regions. Findings: The authors find different industry specialists depending on the geographical region in which the audit firm is located. The Europe, Middle Eastern and Africa region has the highest number of industry specialists and the Asia-Pacific region the lowest. Notwithstanding the global participation of Big 4 firms, assurance specialization depends on the country where the company is located. Research limitations/implications: The paper reveals the need to include regional differences in the analysis of the SAM at the international level. Practical implications: The study shows an in-depth study of the SAM that may be useful for assurers, to decide strategic actions in industries and countries and for regulators, to control the risk of monopolistic/oligopolistic markets. Originality/value: The study presents a novel approach to the analysis of the assurance market for SRs, by studying it from the supply point of view. The analysis provides a measure of specialization that may help understand the structure of the SAM.