本文建立一個混合寡占模型，探討一家部分由外資持股的公營廠商及一家純民營廠商進行價格與數量競爭時福利水準的高低。我們的研究結果顯示，當外資持股比例相對較高（低）時，兩家廠商在數量競爭下的利潤會高於（低於）價格競爭。再者，當外資持股比例介於中間值時，兩家廠商從事數量競爭時的社會福利會較價格競爭為高。此一發現與過去文獻中公營廠商為純公（民）營時，廠商進行價格競爭下的社會福利較數量競爭下高的結果有很大的不同。

This paper reexamines the relative welfare outcomes under Bertrand and Cournot competition in a differentiated mixed duopoly when foreign investors hold ownership in the public firm. The findings indicate, somewhat unexpectedly, that the two firms’ profits are higher (lower) under Cournot competition than under Bertrand competition when the foreign ownership ratio is high (low). Moreover, when the foreign ownership ratio falls to a medium level, welfare is higher under Cournot competition than under Bertrand competition. This result is more likely to occur when the products become more differentiated.