本論文希望透過股權分散的變化，來預測下週或是下月的股價報酬率。因為，假設流通在外股數不變下，當股份從眾多持有少量股票的散戶，集中至持有大量股票的大股東或法人時，集保總人數會下降。而我們認為可以透過觀察集保總人數的變動率，來推測法人及大戶整題而言對該股票的預期方向，因為交易往往伴隨著成本，假設投資人為理性下，法人及大戶會買進或賣出股票往往是因資訊的流入，使得他們認為需要調整持股部位。 透過迴歸模型中的普通最小平方法，當週集保人數減少1%，下週股價報酬率平均而言顯著上升0.055%，年化後的報酬率為2.86%。而當月集保人數減少1%，下個月股價報酬率平均而言顯著上升0.074%，年化後的報酬率為0.89%。由上述結果，可以推斷集保總人數的變化，在統計上會顯著影響下週或下月的股價報酬率。另外，欲瞭解此指標是否適用於所有產業，發現使用上需避開造紙工業及資訊服務業，因該產業之迴歸分析結果為顯著正相關，無法與原先的假設推斷一致。 / Several researches discuss the predictability of the movement of institutional investors and major shareholders because they probably have better ability to analyze the stock or to gather relevant information. However, it is difficult to observe what they are doing especially major shareholder that don’t have obligation to disclose their holding rate. As a result, we wonder if the change in shareholders’ number implies the view of major players in stock markets. The empirical result demonstrates that decrease in shareholders’ number accompanied by positive stock return next period in a significant level which is in accordance with the economic intuition that we suppose the total number of shareholders could reflect the transition of stock shares from many individual investors to some major shareholders. Furthermore, there are systematic cross-industrial differences in the stock return reactions to the prior change of shareholders’ number. In spite of that, all of the industries with negative relationship reach significant level but the industries with positive relationship don’t.