Theory shows that vertical integration has contrasting two effects, efficiency and foreclosure effects. This study empirically estimates the relative size of these two effects. Unlike previous studies, I focus on a single vertical merger in order to use a panel dataset, and estimate its average treatment effects on the several market outcomes. The findings suggest that there was a significant efficiency gain from the merger; the merged systems were found to carry affiliated networks more frequently; there was a larger price decrease in the merged markets. On the other hand, there was weak evidence of foreclosure.
