The oligopoly of academic publishers persists in exclusive database

Global scholarly publishing has been dominated by a small number of publishers for several decades. We aimed to revisit the debate on corporate control of scholarly publishing by analyzing the relative shares of major publishers and smaller, independent publishers. Using the Web of Science, Dimensions and OpenAlex, we managed to retrieve twice as many articles indexed in Dimensions and OpenAlex, compared to the rather selective Web of Science. As a result of excluding smaller publishers, the 'oligopoly' of scholarly publishers persists, at least in appearance, according to the Web of Science. However, both Dimensions' and OpenAlex' inclusive indexing revealed the share of smaller publishers has been growing rapidly, especially since the onset of large-scale online publishing around 2000, resulting in a current cumulative dominance of smaller publishers. While the expansion of small publishers was most pronounced in the social sciences and humanities, the natural and medical sciences showed a similar trend. A major geographical divergence is also revealed, with some countries, mostly Anglo-Saxon and/or located in northwestern Europe, relying heavily on major publishers for the dissemination of their research, while others being relatively independent of the oligopoly, such as those in Latin America, northern Africa, eastern Europe and parts of Asia. The emergence of digital publishing, the reduction of expenses for printing and distribution and open-source journal management tools may have contributed to the emergence of small publishers, while the development of inclusive bibliometric databases has allowed for the effective indexing of journals and articles. We conclude that enhanced visibility to recently created, independent journals may favour their growth and stimulate global scholarly bibliodiversity.