Although studies have shown that it should be possible to financially su-stain an Open Access research environment with the expenditure that is already being spent on subscriptions, it is to be expected that on an institutional level the changeover may bring about financial difficulties. In order to avoid a situation where open access publishing is completely put on hold due to such constraints, we can pave the way for a smoother transition to openness by introducing transitional business models, sup-ported by central funds. The paper describes the prerequisites for an equitable and appropriate use of central funds for such transitional business models, and presents a case study of a currently running, successful agreement. [ABSTRACT FROM AUTHOR]