In the innovation literature, the development of innovation models is subdivided into generations. Until now, we have distinguished three generations. Because current models provide a poor representation of what happens in today's open innovation networks, there is a growing need for a fourth-generation concept. So far, requirements for next-generation concepts have been discussed but well-defined models have not reached the open literature yet. This paper describes a fourth-generation innovation model, which describes the innovation regime by a 'circle of change'. It links changes in scientific insights, technological capabilities, product design and manufacturing, and markets. The model replaces the traditional chain concept by a circle with four 'nodes of change', connected by four interacting 'cycles of change'. Collectively, they may be seen as the arena of opportunity with processes crossing traditional boundaries. These processes have a cyclic nature and are representative of today's open innovation.