本文建構了一個廠商為混合企業（mixed enterprises）的三國兩廠商模型，來探討民營化程度對於國際租稅競爭的影響。依據本文獲致的研究結果顯示：，當廠商的競爭模式屬於數量（價格）競爭時，民營化效果會抵消（強化）利潤移轉效果，使得公共財的提供水準有別於過往文獻所獲致的結果。特別在民營化程度較低時，數量（價格）競爭模式下的利潤移轉效果未必會惡化（提高）公共財的提供水準。另外，在兩國合作模型的架構下，不論是數量競爭或價格競爭，民營化與利潤移轉兩種效果對社會福祉的影響皆不明確，換言之，縱使政府進行租稅合作，稅率的調升不必然會提高社會的福利水準。

To study the effect of privatization on tax competition, we set up a two-stage game model. Two exporting country governments decide their domestic capital tax rates to provide public goods on the first stage. And then, two public firms decide their output/price to maximize their profit function based on these tax rates decided by governments. To obtain solutions of subgame-prefect equilibrium, we use the backward method to solve our models. Our research has different results with traditional conclusions in the past. First, the privatization effect will offset (aggravate) the rent shifting effect when the oligopoly competition model is a quantity (price) competition. Particularly, when the level of privatization is lower, the rent-shifting effect do not definitely aggravate (ease) the under-provision of public goods when firms compete in terms of quantity (price). Furthermore, if two governments can cooperate in the capital tax rate, namely the capital tax rate decided by two governments together, the increase in the capital tax rate uncertainly increase the two countries' social welfare. It still exists a situation that the increase in the capital tax may drop down social welfare. That is, the under-provision may be aggravated or eased in both quantity competition model and price competition model.