The swift development of integrated reporting as a genre within corporate reporting and the rapid spread of organizations adopting the International Integrated Reporting Council's (IIRC) vision for such shows that corporate voluntary reporting is now moving to a new stage. This provides an opportunity for companies to refine or reveal their hitherto hidden voluntary reporting philosophy by adapting their reporting practices. The motivations for adopting integrated reporting could differ from the legitimation motivations the literature has previously considered to underlie broader social and environmental sustainability reporting. For this reason, this study explores the motivations for companies to shift to integrated reporting or to continue with social and environmental sustainability reporting in terms of voluntary disclosure and legitimacy theory. The analysis employs survival analysis conducted using data from companies listed on the Tokyo and London stock exchanges to explore the relationships between social and environmental performance and the timing and duration of a shift to integrated reporting. The results reveal different motivations underlying voluntary reporting practices between the two countries and across industry sectors. Overall, the findings suggest that the financial transparency and accountability role of integrated reporting proposed by the IIRC has gained traction among Tokyo but not London listed companies. However, there is a trend towards accountability in the shift to integrated reporting consistent with voluntary disclosure theory even for London listed companies at the industry sector level. This supports the view that companies have an incentive to differentiate their voluntary reporting philosophy through different forms of reporting and that legitimacy theory and voluntary disclosure theory are compatible in this regard.

综合报告作为公司报告中的一种类型的迅速发展以及采用国际综合报告委员会 (IIRC) 愿景的组织的迅速传播表明，公司自愿报告现在正在进入一个新阶段。这为公司提供了一个机会，通过调整他们的报告实践来完善或揭示他们迄今为止隐藏的自愿报告理念。采用综合报告的动机可能不同于文献先前认为作为更广泛的社会和环境可持续性报告基础的合法化动机。为此原因，本研究从自愿披露和合法性理论的角度探讨了公司转向综合报告或继续进行社会和环境可持续性报告的动机。该分析采用生存分析，利用东京和伦敦证券交易所上市公司的数据，探索社会和环境绩效与向综合报告转变的时间和持续时间之间的关系。结果揭示了两国和跨行业部门自愿报告做法背后的不同动机。总体而言，调查结果表明，IIRC 提出的综合报告的财务透明度和问责制作用在东京上市公司中获得了关注，但在伦敦上市公司中却没有。然而，在向符合自愿披露理论的综合报告转变的过程中，即使对于伦敦上市公司在行业层面上也存在问责制的趋势。这支持了这样一种观点，即公司有动力通过不同的报告形式区分其自愿报告理念，并且合法性理论和自愿披露理论在这方面是兼容的。