Many organizations are planning to engage in the monetization of data. However, it turns out to be a practical problem where to start and what to build on from the existing capabilities. A maturity model helps assess the maturity of the actual capabilities. At the same time the same model can be used to prescribe a desired target state. The gap between the target state and the actual status helps setting up actions to remedy the situation. This paper proposes a Data Maturity Model (DMMM), the first maturity model for data monetization. It has been sci-entifically developed bottom up based on literature and extensive expert knowledge and its first release is extensively documented here.