Open Access Monitor project (OAM-DK) The project highlights the results of monitoring the publishing ecology of Open Access and the scale of the financial resources being spent on Open Access publishing by Danish universities with a parallel look-out to similar efforts in the UK, Sweden and Norway. In a changing landscape of new Open Access modes, Denmark has adopted a so-called “green” strategy, according to which publication must be kept largely free of charge and publications must be archived in institutional repositories. Even so, Danish universities spend significant financial resources on Open Access publishing. Substantial fees are being paid to publish via the “golden route” in born-open journals, but also in subscription-based journals via the hybrid model. The latter is especially interesting considering the practice of double-dipping, where universities not only pay for the right-to-read (via the national e-license portfolios) but also for the right-to-publish (via publication fees). This raises the question of the scale of resources spent on Open Access publishing by Danish universities. This DEFF project follows similar efforts in the UK, Sweden, Norway, Germany and the Netherlands, monitoring how much is being spent on golden and hybrid publishing by Danish universities. The approach has been to identify the publishing ecology of Open Access and derived financial costs. Since it is difficult to gather invoice data, an economic model has been developed to estimat