CCC reached out to Jackie Marchington, Head of Compliance and Ethics at UK-based Omnicom Health, for her perspective on this question.
In my experience, it is likely not the case that the client who sponsored the publication would own the copyright. Copyright is a creator right. In other words, the author of the manuscript is the copyright owner. The client/company may acquire a copyright stake if their employee authored the manuscript since employers typically hold copyright on work created by employees during the course of their employment. With all that said, copyright is often transferred from the author to the publisher as part of the journal article acceptance process. The author (or authorized signatory from the company, if there is a company author) signs a copyright transfer agreement that assigns the copyright to the publisher of the content. I’ve found that even content published under a Creative Commons (CC) license, particularly if the license includes the non-commercial (NC) or no derivatives (ND) clause, journals often require a publishing agreement, alongside the CC license, that transfers economic and other rights in the manuscript to the publisher. On that basis, the sponsoring company will need permission from the publisher for any future use of the published material.