SUMMARY
The concept of sustainability has evolved to encompass environmental, social and governance issues regarding corporate behaviour. For the last few years, stakeholders have begun putting pressure on companies to report on sustainability issues. Several national and international regulations and standards have been adopted to guide companies in their reporting. To ensure the accuracy and comparability of non-financial data needed for the stakeholders’ decision making process, there is an increasing preference for the external assurance of sustainability reporting. The internationally recognized CSR report assurance standards are the International Standard on Assurance Engagements, ISAE 3000, and AccountAbility’s AA1000 Assurance Standard (AA1000AS). This study focuses on the evolution of corporate sustainability reporting, using two non-financial indicators: ESG reporting, and Assurance of ESG reporting. The data for the study is based on content analysis of both CSR reports and corporate websites, courtesy of Sustainalytics. We assessed the evolution of the two indicators from June 2010 to February 2014, for 50 listed European companies and 50 American ones. For the selected time period, US companies are shown to be worse reporters than European ones, having a negligible number of reports externally verified. Considering that for most European countries, guidelines and regulations concerning ESG reporting have already been put in place, there is a positive trend for both ESG reporting and its quality.