Academic journal publications may be retracted following institutional investigations that confirm allegations of research misconduct. Retraction notices can provide insight into the role institutional investigations play in the decision to retract a publication. Through a content analysis of 7,318 retraction notices published between 1927 and 2019 and indexed by the Web of Science, we found that most retraction notices (73.7%) provided no information about institutional investigations that may have led to retractions. A minority of the retraction notices (26.3%) mentioned an (...) institutional investigation either by journal authorities (12.1%), research performing organizations (10.3%), joint institutions (1.9%), research integrity and ethics governing bodies (1.0%), third-party institutions (0.5%), unspecified institutions (0.4%), or research funding organizations (0.1%). Comparing retraction notices issued before and after the introduction of retraction guidelines by the Committee on Publication Ethics (COPE) in 2009 revealed that those published after the guidelines’ publication were more likely to report investigations by journal authorities. Comparing retraction notices from different disciplines revealed that those from social sciences and the humanities were more likely to disclose investigations by research performing organizations than those from biomedical and natural sciences. Based on these findings, we suggest that the COPE retraction guidelines in the future make it mandatory to disclose in retraction notices institutional investigations leading to retractions. (shrink)