本文在公民合營的架構下，重新檢視利潤稅中立性的問題。經由模型的推導分析，我們發現三項重要的結論：其一，在一般化的效用函數下，當廠商考慮公股的社會福利目標時，可以得到廠商生產與逃漏稅決策間不必然具有可分離性，而且利潤稅中立性不必然成立的論點。其二，當效用函數取決於淨利潤與社會福利的線性組合時，雖然廠商的生產與逃漏稅決策間具有可分離性，但利潤稅的中立性不必然成立，意即可分離性與中立性之間並不存在對應性。最後，若廠商面對公司稅制而非利潤稅制，則廠商的生產與逃漏稅決策的關係將從可分離性轉變為不可分離性。

This paper reexamines the issues of neutrality of profit taxes and separability for a monopolistic firm by taking stockholder’s structure into account. It is shown that in the presence of the mixed enterprise, we find that, first, the firm’s production and evasion decisions will not be separable from each other, and profit taxes will not be neutral. Secondly, when the utility function depends on the linear combination of net profit and social welfare, the inseparability result does not necessarily imply the neutrality of profit taxes. Finally, if the profit tax system is replaced by the corporate tax system, then the relationship between production decisions and evasion decisions shifts from separability to inseparability.