While open access journals provide readers with articles free of charge through the journals’ networks, authors are required to pay article processing charges to the publishers. This study simultaneously estimates the article processing charges for 535 open access journals independently launched by publishers along with citation scores and number of articles in a journal to identify the determinants of charges. The results show that open access journal publishers set higher article processing charges for more frequently cited journals with more articles. However, concentration measured by the share squared of the number of articles in an academic field is not shown to influence the charges significantly. Moreover, this study finds that large subscription journal publishers do not generally set higher article processing charges for their open access journals. Instead, they incorporate open access journal publishers that have already accomplished great achievements into their company groups. These findings suggest that large subscription journal publishers may influence the open access journal market through mergers and acquisitions of prominent open access journal publishers in the future, although they do not yet have market power.