This study investigates the relationship between resource concentration/stability and new results/breakthroughs in the context of a Swedish Center of Excellence (CoE) scheme. A common assumption in using the CoE instrument is that there is a scale return to research on concentration of funds. However, the details of how funding connects to such returns are typically assumed rather than empirically investigated. The present qualitative study sets out to identify the mediating mechanisms connecting organizational capacities made possible through the CoE grant (e.g. recruitment/human capital, data/infrastructure and various collaborative arrangements), and epistemic effects such as extension into new problem areas and higher degrees of risk taking in research generally. We conclude that a CoE program theory can be conceived in terms of resource stability yielding research flexibility, and that the common mechanisms connecting the two may be found in organizational arrangements facilitating slack (autonomy), availability of cooperative partners (critical mass) and concomitant cooperation between specialisms. It is our belief that by explicating such mechanisms CoE program theory can be greatly improved.