David Solomon has published "Types of Open Access Publishers in Scopus" in Publications.
Here's an excerpt:
This study assessed characteristics of publishers who published 2010 open access (OA) journals indexed in Scopus. Publishers were categorized into six types; professional, society, university, scholar/researcher, government, and other organizations. Type of publisher was broken down by number of journals/articles published in 2010, funding model, location, discipline and whether the journal was born or converted to OA. Universities and societies accounted for 50% of the journals and 43% of the articles published. Professional publisher accounted for a third of the journals and 42% of the articles. With the exception of professional and scholar/researcher publishers, most journals were originally subscription journals that made at least their digital version freely available. Arts, humanities and social science journals are largely published by societies and universities outside the major publishing countries. Professional OA publishing is most common in biomedicine, mathematics, the sciences and engineering. Approximately a quarter of the journals are hosted on national/international platforms, in Latin America, Eastern Europe and Asia largely published by universities and societies without the need for publishing fees. This type of collaboration between governments, universities and/or societies may be an effective means of expanding open access publications.