公用天然氣事業資金成本率之探討

本研究主要探討法定天然氣事業資金成率公式之合理性。根據我國公用天然氣事業天然氣售價及基本收費計算準則，天然氣事業計算業主權益報酬率時，固定以百分之三點七作為天然氣事業之風險貼水，然而該比率並沒有隨天然氣事業之經營狀況及市場環境而改變。不同於法令制定的當下，近幾年天然氣產業經營的狀況與全球對於天然氣需求的改變可能使風險貼水不再是當初評估的百分之三點七。因此本研究蒐集了台灣近15年來6家上市櫃天然氣瓦斯公司之財務資料，並使用資本資產定價模型以及股利固定成長模型計算出各家公司之Beta值以及業主權益報酬率。發現無論在何種基礎下，法定資金成本率之公式對2家上櫃公司較有利，但對於4家上市公司部分則較為不利。因此本文建議政府應規定以一個適當之期間作為基礎，並於每一個期間重新評估公用天然氣事業之風險貼水，以符合公用天然氣事業實際上所面臨之經營狀況與市場環境。

關鍵字

公用天然氣事業；資本資產定價模型；股利折現模型；資金成本率；風險溢酬

並列摘要

This paper examines the rationality of the fair return in public natural gas utilities. According to the Natural Gas Enterprise Act in Taiwan, we use 3.7 percent as the public natural gas utilities’ risk premium to calculate the equity return of the public natural gas utilities. However, the risk premium isn’t adjusted with the operating situation and change of market demand. This paper collects the financial data from six public companies from 2003 to 2017 and analyzes the beta of CAPM and equity return of each company from CAPM and Gordon model. The results show that the 3.7 percent risk premium is beneficial to two listed company at over-the-counter market and harmful to four listed company at stock exchange market. This paper suggests that the government should reassess the risk premium with a period that is more appropriate. If the government could assess the public natural gas utilities’ operating situation and market environment in an appropriate period, the risk premium would be more suitable for the actual situation.