考慮內生要素和環境變數問題下探討我國銀行業經濟效率

本研究改良Amsler et al. (2016, 2017) 的模型，將生產要素與環境變數具有內生性問題，納入投入面方向距離函數與成本函數，分別探討我國銀行業2002-2019年的技術與成本效率，配置效率隱含在上述兩種效率之差額。推導出誤差項的機率密度函數後，採用最大概似法進行估計並計算各種效率值。實證分析結果支持方向距離函數應考慮內生要素與環境變數，成本函數也應考慮內生環境變數。樣本銀行的配置無效率比技術無效率嚴重，尤以泛公營銀行最高，外商銀行最低；將樣本期間切成兩部分，發現除外商銀行外，各種效率值有惡化趨勢；樣本銀行享有規模與範疇經濟，擴大營運規模與產品多樣化，有利降低營運成本。  In this study, we modified the model proposed by Amsler, Prokhorov, and Schmidt (2016, 2017) to consider endogenous inputs and environmental variables in directional input distance and cost functions. Compiling data from Taiwan’s banking industry, spanning 2002-2019, we estimated technical, cost, and allocative (in)efficiency measures for sample banks. The maximum likelihood estimation was adopted to obtain the parameter estimates for the above two functions. Empirical results support that the distance function considers endogenous inputs and environmental variables and that the cost function involves endogenous environmental variables. The average value of allocative inefficiency was higher than technical inefficiency, where foreign banks were the most allocatively efficient, followed by private and pan-public banks. The various inefficiency measures tended to deteriorate over time. Since economies of scale and scope prevail in the industry, we recommend that the sample banks expand their operating scale and diversify their financial products to lower the long-run average cost.