In this paper we consider how the location, organization and output of knowledge production evolve within domestic firms following acquisition-FDI in order to understand the aggregate effect on an index of domestically produced innovations. We find strong differences according to how close the acquiring MNE is to the technologically frontier. Frontier MNEs are more likely to close R&D activities in acquired affiliates, but when they are retained they expand employment of high-skilled R&D workers and transfer R&D knowledge. Non-frontier MNEs make fewer changes to R&D. Overall the effect of acquisition-FDI on the domestic innovation index is positive.