本研究旨在探討投資組合的設計，故以2010年1月至2019年6月台灣各上市公司、電子類股及非電子類股之每季稅後淨利率為投資組合選取準則，觀察投資組合的績效。研究發現稅後淨利率能確實體現各上市公司的獲利能力指標；換言之，不能僅考量營收水準，而須進一步分析營業成本、營業費用、業外支出、所得稅等各項成本要素。基本上，本研究實證結果如下：以淨利率為投資策略時，以小型高淨利率公司之報酬績效最高；以累積報酬走勢圖觀察，發現採用淨利率變動策略對投資電子股公司有較高的報酬績效；景氣循環會顯著影響投資績效；多頭市場與空頭市場也會顯著影響投資績效。 This study tends to design the investment portfolio. Therefore, we use the 10 years quarterly net profit margin data of Taiwan's listed companies, electronic stocks and non-electronic stocks, as the selection criteria for investment portfolios to observe the performance. In other word, the portfolio design should be based on the net profit margin, not only consider the operating costs, operating expense, non-business expenditure, income tax. Generally, the results of this research are as following: Using net profit margin as an investment strategy, the performance of small high net profit margin company is the highest. Observing the cumulative return chart, it is found that the use of the net profit margin strategy has a higher return performance on the investment in electronic companies. Business cycle can significantly affect investment performance. Long and short markets also affect investment performance significantly.
