Mergers and Innovation: An Exploration of Scope and Direction of Innovation

Abstract

How do mergers change the scale and composition of firm innovation? We study U.S. public mergers from 1980 to 2020 using combined acquirer-target patent portfolios. We measure scope, the scale of the joint portfolio, and direction, its alignment with highly cited patents. A compact portfolio model isolates three forces: product-market business stealing, technological knowledge pooling, and fixed costs of activating innovation lines. Business stealing can reshape private returns where the firms already compete. Knowledge pooling raises the productivity of post-merger R&D where technologies are related. Activation lets the merged firm open innovation lines that were not worth running before the merger. The model also speaks to reallocation: how post-merger effort is split between lines already shared by both firms and lines unique to one. The model leaves the average change in that split unsigned, and it leaves the average change in direction unsigned as well. We compare treated merger pairs to matched control pairs. Empirically, on the matched sample, joint-portfolio scope is larger after mergers than for matched controls. The difference is substantially larger when pre-merger technologies are more related, especially among non-horizontal deals. We find no strong evidence of reallocation. Innovation activity expands after mergers, without a clear rebalancing of activity between technology classes shared by both acquirer and target and classes unique to one. On direction, joint portfolios show higher alignment with highly cited patents relative to matched controls. Acquirer-only R&D measures overstate post-merger input growth relative to joint-entity measurement.