Causes and consequences of voluntary assurance of CSR reports: International evidence involving Dow Jones Sustainability Index Inclusion and Firm Valuation

PurposeThe purpose of this paper is twofold. First, the authors investigate a firm’s decision to provide a CSR report, and if so, whether to have the report assured and to seek higher quality assurance as reflected through the choices of the scope of the assurance and type of assurer, Big 4 accounting firm vs specialist consultant. Second, the authors investigate the impact of voluntary assurance of CSR reports, assurance scope and type of assurer on the likelihood of inclusion in the DJSI and on market valuation.Design/methodology/approachThe study’s sample consists of 17,050 firm-year observations from 40 countries with CSR reports available from Corporate Register and ESG metrics available from ASSET4 over the period 2009–2015. The study first empirically examines the associations between CSR commitment and each of CSR report provision, CSR report assurance, assurance scope and type of assurer. It then examines that association between both inclusion in the DJSI and market valuation with each of CSR report assurance, assurance scope and type of assurer, using inclusion in the DJSI as an objective measure of a firm’s reputation for sustainability given its recognition as a leading indicator for corporate sustainability and market valuation as a reflection of the broader set of capital market participants.FindingsThe authors establish two key findings consistent with the predictions of signaling theory. First, we show that high CSR commitment firms are more likely to: provide standalone CSR reports; obtain assurance; obtain assurance from a Big 4 accounting firm; and, adopt higher assurance scope. Second, the authors find that both CSR report assurance and assurance scope increase the likelihood of inclusion in the DJSI, but that the type of assurance provider does not. Alternatively, the authors find that capital market participants appear to value the provision of a CSR report only when it is assured by a Big 4 accounting firm.Originality/valueThe results in the existing literature exploring the capital market benefits to CSR Assurance have been mixed. Firms that voluntarily obtain CSR Assurance incur a cost in doing so and must perceive a net benefit from obtaining such assurance. Despite the limited guidance currently provided by existing CSR standards, we establish the existence of benefits to obtaining CSR Assurance in terms of enhanced likelihood of DJSI inclusion and, more generally, enhanced market valuation. The discussions with DJSI analysts in