本文分析獲選為天下雜誌最佳企業公民之 30 家上市公司的股票報酬，評估這些公司在評 等結果公佈日附近的短期宣告效果，以及長期股價表現是否較那些未入選的公司要來得好。實 證結果發現，30 家公司在評等結果公佈日當天的平均異常報酬，以及公佈日前數日、公佈日後 數日的累積平均異常報酬並不顯著，而就長期股票報酬而言，30 家公司的表現並沒有比未入選 的其他公司要來得好。這個現象，即使是透過重新建構與入選公司特性變數相類似的未入選公 司配對樣本，或是考量投資報酬率的風險，仍未有明顯的改變。因此我們的結論是，不論是短 期或是長期，最佳企業公民之 30 家公司的投資人或股東，並無法獲得較高之投資報酬，因此 善盡企業社會責任的好公司不一定是個好的投資標的。 2.This paper examines the stock performance of 30 TWSE-listed companies among Taiwan's Best Corporate Citizens from the 2007's survey by Common Wealth magazine. We examine both short-term announcement effects around the time of the survey's publication, and whether longer-term returns are higher for firms that are listed as good citizens. We did not find evidence of a positive market reaction to a firm's presence in the top 30 firms, and there is also no long-term return superiority against non-top 30 firms. This principal outcome unchanged as we use matching theory to construct samples of similar in characteristics non-top 30 firms and consider risk-adjusted stock returns. We conclude that stockholders and investors of top 30 firms cannot get higher returns than non-top 30 firms by buy-and-hold strategy, and thus implies that companies taking corporate social responsibilities are not necessarily good investments.
