Scholars emphasize the importance of psychological ownership (i.e., a feeling of possession towards an object independent of legal ownership) for desired behaviors and attitudes in corporate contexts. Psychological ownership is a multi-level phenomenon, meaning that the emotional attachment it implies might pertain to the overall organization as well as to organizational sub-units (e.g. business units). Hitherto, however, there is little empirical evidence on the antecedents, consequences, and vertical spillover effects of psychological ownership. To address this research gap, our paper presents arguments explaining how psychological ownership positively affects organizational performance by diffusing from higher levels of the organization towards lower levels. Furthermore, we suggest that error management culture and high affective commitment within teams, constitutes environmental conditions that let psychological ownership thrive. To test our theorizing, we created a unique dataset combining archival data with two surveys among 1,536 employees and 66 managers of an organization. Our results indicate that psychological ownership towards the business unit indeed enhances performance and mediates the effect of psychological ownership towards the entire organization. Additionally, our findings suggest that error management culture and the increase of affective commitment in teams pose mechanisms that can enhance psychological ownership towards the business unit. With these findings, our study yields important theoretical and practical implications.