A start-up engages in an investment portfolio problem by choosing how much to invest in a "rival" project, which threatens the position of an existing incumbent, and a "non-rival" project. Anticipating its acquisition by the incumbent, the start-up strategically distorts its portfolio of...

The structures of social interaction affect individual behavior and economic performance in important ways. This leads us to ask: does the architecture of social interaction exhibit particular patterns and are these patterns stable over time? We examine interaction among economists by looking at...

This paper studies mergers in markets where firms invest in a portfolio of research projects of different profitability and social value. The portfolio nature of the investment problem brings about novel insights on the external effects of firms' investments. The investment of a firm in one...