以產業專精度探討本土與外資券商的盈餘預測績效

我國自1991年起開放外資券商於本國投資，投資人普遍認為外資券商相對於本土券商較具有專業知識，但過去研究並未提出具體指標衡量兩者之產業專精能力。因此，本研究以赫芬達指數（Herfindahl Index，簡稱 HI指標）具體比較本土券商與外資券商的產業專精程度，並進一步探討其對本土與外資券商盈餘預測績效的影響。研究結果顯示：1. 整體券商樣本之產業專精度愈小時，盈餘預測準確度愈高。更進一步分類發現，外資券商還是以產業專精度愈高者，其預測準確度愈高，而本土券商則相反，說明其他因素對本土券商準確度影響更大。2. 本土券商在資訊的掌握上較外資券商具地理優勢，使得其發佈的盈餘預測準確度較高。3. 處於市場多頭時，當券商預測愈頻繁、預測公司家數愈多及預測產業數愈少時，準確度愈高；而處於空頭時，由於券商對於科技業市場變遷更為審慎，使其預測準確度較高。

關鍵字

產業專精；盈餘預測準確度；外資券商；本土券商

並列摘要

Since 1991, foreign brokerages have been permitted to invest in Taiwan. Generally, investors believe that foreign brokerages are more professional and specialized than local ones. However, there is no objective indicator in past literature to measure the industry specialty for both of them. Therefore, this paper refers to the Herfindahl Index (HI) to compare industry specialty between local and foreign brokerages, and explores their earnings forecast accuracy. The results show that the lower industry specialty of brokerages in the whole sample resulted in higher earnings forecast accuracy. However, the higher industry specialty of foreign brokerages resulted in higher earnings forecast accuracy. There should be other factors that influence the earnings forecast accuracy of local brokerages. Next, we find that local brokerages have a geographical advantage in collecting information to forecast more accurately than foreign brokerages. In a bear market, brokerages that are more cautious about the change of technical industry results in higher earnings forecast accuracy.