本文分析外資投資決策如何影響公司營運效率與績效表現。實證發現：外資持股與營運效率有顯著相關。營運效率扮演部份中介效果。當持股進入穩定成熟期時，外資對營運效率有較重的影響力：長期持股存量有助營運效率與績效表現；短期持股變動量則對營運造成督導效果。外資在新興市場中產生外溢效果，改善公司營運效率與績效。 Using data envelopment analysis, this article examines the influence of foreign investors on corporate operational efficiency and performance. This study identifies a significant correlation between corporate operational efficiency and foreign investment shareholding ratios. Corporate operational efficiency plays a mediating role between foreign investors and performance. When foreign shareholdings achieve a stable and mature stage, the long-term foreign investment shareholding stock facilitates the enhancement of operational efficiency, whereas short-term shareholding variation levels create pressure or monitoring and disciplinary effects for corporate operations. Overall, in Taiwan market, foreign investors could have spillover effects on listed companies and raise their efficiency and performance.