Using an experimental design, this explorative study provides unique empirical evidence of the effects of an integrated reporting assurance (IRA) on nonprofessional investors’ (NPIs) financial decision-making in a laboratory experiment. For this purpose, two independent experiments were carried out, one relying on a sample of Master’s students, and one focusing on managers of large corporations. In line with our agency theoretical reasoning, we find that students value an IRA positively, evidenced through significantly higher investments, while, contrary to expectations, an IRA has the opposite effect for managers. The results reveal that, dependent on the empirical model, an IRA has either no, or even an investment-decreasing, impact on executives. In order to assess the sense-making process underlying this conundrum, subsequent interviews with the managers were carried out which revealed three dimensions that shape practitioners’ critical attitudes towards assurance engagements. First, managers expressed a general disbelief in the decision usefulness of integrated reporting (IR) to (nonprofessional) investors. Second, interlocutors referred to negative practical experiences with audit and assurance engagements and had technical doubts specific to IRA. Third, managers voiced emotional caveats regarding the audit and assurance profession. These findings indicate a prevailing divergence between the extolled theoretical contribution of an IRA to report credibility and its actual nature in practice. In the further course of the investigation, we also find that the assurance provider (Big 4 auditor versus specialized consultant) does not affect investment decisions, but that a higher assurance level leverages investments among students. The results of this study add to the growing, albeit still small, IRA research body and deliver valuable insights for research, regulators, and practice.

使用实验设计，这项探索性研究提供了在实验室实验中综合报告保证 (IRA) 对非专业投资者 (NPI) 财务决策影响的独特经验证据。为此，进行了两项独立的实验，一项以硕士生样本为样本，一项以大公司经理为对象。根据我们的代理理论推理，我们发现学生对 IRA 的评价是积极的，这可以通过显着更高的投资来证明，而与预期相反，IRA 对经理的影响则相反。结果表明，根据经验模型，IRA 对高管没有影响，甚至投资减少。为了评估这个难题背后的意义构建过程，随后对管理人员进行了采访，揭示了塑造从业人员对鉴证业务的批判态度的三个方面。首先，经理们普遍不相信综合报告 (IR) 对（非专业）投资者的决策有用性。其次，对话者提到了审计和鉴证业务的负面实践经验，并对 IRA 有特定的技术疑虑。第三，管理人员对审​​计和鉴证行业表达了情感上的警告。这些发现表明 IRA 对报告可信度的夸大理论贡献与其在实践中的实际性质之间普遍存在分歧。在进一步的调查过程中，我们还发现保证提供者（四大审计师与专业顾问）不影响投资决策，但更高的保证水平会利用学生之间的投资。这项研究的结果增加了不断增长的 IRA 研究机构，尽管它仍然很小，并为研究、监管机构和实践提供了有价值的见解。