Five anonymised case studies from not-for-profit journals publishers in life sciences and physical sciences, across the world. Looks at the breakdown of APCs into the various elements of cost, per article, and the surplus (if any) returned to the society, also per article. It looks at key factors, such as the extent to which their mission drives their OA program, how bound they are by legacy systems and procedures, and the costs of various outsourced components like delivery, composition and peer review software.