自然獨占之可維持性價格與經濟管制理論之研究

Abstract

美國國會於1978年通過航空解除管制法案(the Airline Deregulation Act of 1978)，結束自1938年開始對航空業之經濟管制。而在地面運輸方面，由州際商務委員會 (Interstate Commerce Commission) 於1887年開始的經濟管制措施，也在1995年通過ICC終止法案(the ICC Termination Act of 1995)後宣告結束。為何美國要結束運輸產業的經濟管制？在實務上，航空解除經濟管制後，業者相互競爭不僅降低費率，更促使航空業者採行較有效率之軸輻式(hub-and-spoke)路線結構；而鐵路運輸放鬆經濟管制(the Staggers Act of 1980)後，也使得費率降低且業者利潤提高。美國之所以能夠完成運輸業之解除經濟管制運動，多有賴於經濟學家的理論研究。就經濟理論上來說，並非所有的獨占產業都需要管制，以獨占產業成本特性來區分，可分為強自然獨占與弱自然獨占。其中又可再細分成有進入障礙與無進入障礙兩種情況。當產業是屬於無進入障礙且定價在可維持價格集合內時，就不需要對此產業執行任何的經濟管制措施。 本研究分為兩部分，前半部份主要屬於規範性理論，嘗試引介自然獨占之可維持性概念，作為運輸經濟管制與否之機制。在探討可維持價格是否存在情況時，考量運輸產業常發生之交叉補貼現象與可爭奪市場之條件，常採用的價格為福利最大價格，即萊姆西價格。雖然可維持價格與萊姆西價格間並沒有直接關聯，卻是追求福利最大管制者所應關注的。對於可維持價格解存在條件，藉由賽局理論可嘗試求出可維持價格存在下之充分條件與必要條件。 對於本質上不應該有經濟管制的產業，實際上卻有管制行為的發生，可以採用管制經濟的實證性理論來解釋，此為本研究後半部的研究課題。在發生管制行為的實證分析上，有許多理論嘗試找出經濟管制發生的原因。從規範性分析到捕獲理論，皆無法完整解釋管制行為實際發生的原因。真正可用模型去解釋、預測的為管制經濟理論模型，此模型說明管制行為發生的實際原因並非基於經濟因素之考量，而是由於相關利益團體間的壓力函數，迫使管制者、立法者採許對利益團體有利的管制措施。本研究以國道客運路線開放為例，經由訪談相關人員，以驗證符合管制經濟理論。而由各國解除或放寬管制效果，與我國國道開放效益比較，國內應再朝更放寬經濟管制方向發展。

In 1978, The United States Congress passed the Airline Deregulation Act ending the economic regulation of airline industry since 1938. As for surface transportation, it was the Interstate Commerce Commission Termination Act of 1995 that made the economic regulation by ICC since 1887 to the end. Why did the U.S. Congress remove the economic regulation of transport industries？In reality, after removing the regulation from airline industry, the competition between firms not only made fare decreasing, but also prompted firms to adopt more effective hub-and-spoke route structure. Like the airline industry, the effects of deregulating railroad industry, which based on the Staggers Act of 1980, have been the decreasing fare and higher profit for firms. Owing a great part to the economist's efforts, United States has accomplished the economic deregulation of transport industries. From the economic theory, however, not all monopoly industries have to be regulated. Natural monopolies can be divided into strong and weak ones by its cost function. Moreover, each group can be divided into two classes basing on the existence of barriers of entry. When an industry has no entry barriers and chooses sustainable prices, there is no need to execute any economic regulation. This paper consists of two parts. The first part mainly refers to normative theory by introducing the sustainable price of natural monopoly as key factor to determine whether executing economic regulation or not. When examining the existing of sustainable price, we usually consider subsidy-free price which usually appeared in transport industries and conditions to be a contestable market, and firms generally adopt welfare-maximum price, like Ramsey price. Although there is no direct relationship between sustainable price and Ramsey price, the regulatory agency that pursues welfare-maximum should pay attention to it. Game theory could be used to find out the necessary and sufficient conditions for the existence of sustainable price. It usually occurs that an industry, which doesn't need any economic regulation, from normative point of view, has been regulated in reality. We may use the positive theory of economic regulation to interpret, and this is the essence of the second part of this paper. In the positive analysis, there are many theories seeking the reasons why economic regulation happens. From normative analysis of positive theory to capture theory, all can't completely interpret it. It is the economic theory of regulation that can use model to interpret reasons and predict it. It indicates that the reason of why regulation happens isn't on economic consideration, it is the relative interest groups' pressure functions that push regulatory and legislators to adopt pro-interest group regulation. This paper uses Taiwan's open highway bus policy as an instance. Through discussing with relative persons, we confirm the economic theory of regulation. Comparing the effects with other countries' deregulation, we should move to more regulatory reform.