Abstract : The open access (OA) article processing charges (APC) project is a longitudinal study of the minority of fully OA journals (27% in 2016) that have APCs. The global average APC shows little change; in USD, 906 in 2010, 964 in 2016, 974 in 2017. The average masks currency differences and the impact of a growing market; new APC journals often start with an APC of 0. Traditional commercial scholarly publishers are entering the OA market: the largest OA journal publishers’ portfolios in 2017 were Springer, De Gruyter, Elsevier, and Wolters Kluwer Medknow. However, these are a small portion of OA journal publishing which is still marked by a very long tail and extensive involvement by very small, often university or society publishers. APC pricing shows a wide range and variability. The APC market can be described as volatile.
