Strategic Complementarities in Bank Branching Decisions*

I study how complementarities between rival banks' branching decisions impacts banking deregulation. I use an instrumental variables approach to separately identify a bank's strategic response to rivals' branching decisions from common market factors. The results indicate that some bank types are more likely to open additional branches if their rivals do. This has important implications for expansion and merger policies. These are explored using a model of consumer demand for bank services and bank branch network choices. I find that strategic complementarities in branching decisions augment the effects of a merger or expansion, leading many banking markets to become over-branched.