寡占競爭、環境管制與利益團體

Abstract

本文建構一個兩國三地的寡占模型，容許兩國廠商的污染減量成本可以不同，且廠商會遊說政府以獲得有利的環境政策。在廠商間進行數量競爭、生產的產品為同質的情況下，我們發現，當兩國廠商為成本同質，若政府對於政治捐獻給予的權數較高者，制定的污染排放標準將較寬鬆。而在兩國廠商成本為異質的情況下，若政府對於政治捐獻給予的權數相對較高者，當該國廠商污染減量成本相對較高時，政府會制定較寬鬆的污染排放標準；若政府對於政治捐獻給予的權數相對較低，只要成本差異較大，或成本差異較小且環境損害係數小於一定值，政府會依然制定較寬鬆的污染排放標準，惟若成本差異較小，但環境損害係數大於一定值，縱使該國廠商污染減量成本相對較高，政府反而會制定較嚴格的污染排放標準。\n而在兩國廠商成本相同，但產品為異質的情況下，我們發現，不論兩國廠商係進行數量競爭或價格競爭，若兩國政府對於政治捐獻給予的權數相同，兩國政府制定的污染排放標準相等。若政府對於利益團體給予的權數不同，則政府對於政治捐獻給予的權數相對較高者，會制定較寬鬆的污染排放標準；而政府對於政治捐獻給予的權數相對較低，會制定較嚴格的污染排放標準。

This dissertation constructs a third-market model with oligopolistic competition. In the model, the firms may have different pollution abatement costs, and they can lobby for the governments to obtain favorable regulations. I find that, in the case with Cournot competition and homogeneous goods, the government that attaches a larger weight to the political contributions will set a less stringent policy. The same result occurs, when a country’s firm has higher abatement costs, provided that its government attaches a larger weight to the political contribution. However, when the government attaches a smaller weight to the contributions, the difference in the abatement costs between firms and a sufficiently large marginal environmental damage will lead the government to select a more severe regulation.\nIn the case with heterogeneous products and same abatement costs, I find that, the government that attaches a larger weight to the political contributions will set a less stringent policy. However, if the government attaches a smaller weight to the contributions, then it will choose a more stringent regulation. The same result holds in both Cournot and Bertrand competition model.