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Sustainability reporting serves as a tool for companies to assess and communicate their sustainability-related efforts. However, these reports may lack reliability and value because of their voluntary and mostly unregulated nature. Two major practices have been adopted in order to overcome these weaknesses: First, accompanying the growth in reporting there has been a rise in the proportion of reports that include assurance statements prepared by third parties. Second, in response to the increased complexity and length of stand-alone sustainability reports, there have been moves to combine some social and environmental disclosures with financial disclosures in single reports. This dissertation examines these two practices, which mark recent trends in non-financial reporting and may impact the accounting and sustainability landscape with regard to future disclosure practices. Special attention is paid to investors´ information processing of these issues, their general perception, the content of assurance statements and the rising issue of assuring integrated reports. The thesis contributes to the discussion on integrated reporting and sustainability-related assurance, as well as on theoretical considerations within accounting research. It illuminates perception by primary stakeholders, critically examines current practice and points to upcoming challenges.

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