本研究針對銀行業的分行網路之空間競爭效果，進行實證分析。由於產業內的正外部性與偷生意效應對於分行獲利會造成相反的影響，因此空間競爭效果的理論預測方向模稜兩可。我收集1981到2016年間台灣各銀行所有分行的地址，結合地理資訊座標，對於分行位置的選擇進行量化分析。在控制社經變數之後，估計銀行在各鄉鎮市區的分行數，如何受鄰近其它分行的影響。我發現在同一鄉鎮市區內，對手銀行的分行數會對於獲利有負向影響。然而，周邊鄉鎮市區的自家分行對於獲利則有正向效果，意味著密度經濟的效應可能存在於本產業。

This research aims to empirically analyze spatial competition of branch network in the banking industry. Theoretical prediction of the spatial competition effect is ambiguous because business-stealing effect and positive externality in this industry would have opposite impacts on a bank’s profitability of opening a branch. I collect address information for all bank branches in Taiwan for a 35-year period (from 1981 to 2016). The addresses of all bank branches are geocoded to quantitatively analyze spatial competition in the choice of branch location. Controlling for observed socioeconomic variables, I estimate the effect on the number of a bank’s branches in a township caused by nearby branches operated by own and rival banks. I find that the competition of rival banks’ branches within the same township has a negative but diminishing effect on the profitability of opening a branch. On the other hand, there is a positive effect from branches of the same bank in nearby townships, suggesting the existence of economies of density in this industry.