Innovation: The Bright Side of Common Ownership?

A firm has inefficiently low incentives to innovate when other firms benefit from its innovative activity and the innovating firm does not capture the full surplus of its innovations. We provide conditions under which common ownership of firms mitigates this impediment to corporate innovation. Common ownership increases innovation when technological spillovers are sufficiently large relative to product market spillovers. Otherwise, the business stealing effect of innovation dominates and common ownership reduces innovation. Empirically, product market spillovers (as measured by Jaffe/Mahalanobis proximity in product market space) decrease the effect of common ownership on innovation inputs and outputs, whereas technology spillovers (proximity in patent space) increase the effect. The sign and magnitude of the relationship between common ownership and corporate innovation varies considerably across the universe of firms depending on the relative strength of product market and technology spillovers. When product market spillovers are relatively large, an increase from the 25th to the 75th percentile of common ownership is associated with a decrease of -8.4% in citation-weighted patents. But when technology spillovers are relatively large, the same increase in common ownership is associated with an increase of +12.5% in citation-weighted patents. Our results inform the debate about the welfare effects of increasing common ownership among U.S. corporations.