[目的/意义]在社交平台上分享共有信息已成为一种普遍且不可避免的现象。理解社交平台用户的共有信息披露行为对于提升用户共有信息分享体验及保护集体隐私至关重要。[方法/过程]采用扎根理论方法，通过三级理论编码，从集体视角全面、系统和深入地探究社交平台用户共有信息披露的特征、情境和发生机理，构建涵盖9个主范畴、19个基本范畴和102个初始概念的社交平台用户共有信息披露行为发生机理模型。[结果/结论]共有信息的内容特征、主体特征和受众特征会影响个体的集体收益和风险感知。同时，个体的集体收益和风险感知会直接及通过集体公平评估间接影响个体的共有信息披露行为。此外，个体的共有信息披露行为还受到个体的信息所有权感知和集体隐私应对的直接影响。并且，个体的信息所有权感知和集体隐私应对还会调节集体收益
和风险感知对共有信息披露行为的影响。研究结果丰富了个体信息披露行为的理论框架与研究体系，同时为政策制定者和社交平台开发者等主体提升用户的共有信息分享体验带来一些实践启示。

[Purpose/significance] Sharing co-ownership information on social platforms has become a common and inevitable phenomenon. Understanding the co-ownership information disclosure behavior of social platform users is crucial for enhancing their co-ownership information sharing experience and protecting collective privacy. [Method/process] Adopting the grounded theory method, this study conducts a comprehensive, systematic and in-depth investi⁃gation into the characteristics, contexts and occurrence mechanism of co-ownership information disclosure among so⁃cial platform users from a collective perspective via three-level theoretical coding. On this basis, it develops a model for the occurrence mechanism of social platform users' co-ownership information disclosure behavior, which encom⁃passes 9 main categories, 19 basic categories and 102 initial concepts. [Result/conclusion] This study found that the content characteristics, subject characteristics, and audience characteristics of co-ownership information can affect in⁃dividuals' perception of collective benefits and risks. At the same time, the collective benefit and risk perception of in⁃dividuals will directly and indirectly affect their disclosure behavior of co-ownership information through collective fair⁃ness assessment. In addition, the disclosure of co-ownership information by individuals is directly influenced by their perception of information ownership and collective privacy coping. Moreover, individual perception of information owner⁃ship and collective privacy coping can also moderate the impact of collective benefit and risk perception on co-ownership information disclosure behavior. The results enrich the theoretical framework and research system of individual informa⁃tion disclosure behavior, and provide practical insights for policy makers and social platform developers to enhance us⁃ers'co-ownershipinformationsharingexperience.