Measuring company efficiency is an important issue for both managers and investors. Efficiency measurement is always important because organizations are constantly striving to increase internal productivity. However, investors are more concerned about sustainability than many executives believe. Almost 75% of investment community respondents strongly believed that improvements in operational efficiency were often accompanied by progress in terms of sustainability. This study examined companies listed on the Taiwan 50 and Taiwan Mid-Cap 100 Indexes and measured and ranked their operational efficiencies, identifying representatives with high investment potential among these highly capitalized blue chip stocks from various industries. The results will provide managers with recommendations for improving operational efficiency through competitive mapping, as well as a list of the most attractive targets for investment.