本研究探討彌補虧損減資、現金減資與庫藏股減資等三種減資之市場宣告效果。彌補虧損減資雖於宣告時市場反應不佳，但往後卻漸入佳境，空頭市場中執行現金減資最能凸顯公司良好的體質及財務狀況，而實施庫藏股則能展示對自家公司的信心。三種減資於宣告後之長期股價績效都有轉佳之現象。減資比率於彌補虧損與現金減資公司中分別負向與正向影響異常報酬，但不影響庫藏股減資公司。三種減資決策重點並不在調節公司資本結構。此外，投資人不支持彌補虧損減資公司再付出研發費用。現金減資公司中，董監持股愈高，或盈餘分配權愈小，愈能得到投資人之青睞。庫藏股減資公司的董監質押比例愈低，市場愈趨向正面之評價。

This study explores the market announcement effect of three types of capital reduction, namely capital reduction to write off accumulated losses, cash refund capital reduction, and capital reduction by stock repurchases. Although capital reduction to write off accumulated losses has negative market reactions at announcement, the market reaction improves afterwards. In a bear market, cash refund capital reduction can demonstrate robust corporate health and strong financial position. Stock repurchases is the best way for companies to demonstrate their confidence in the company. All three methods result in improved long-term stock price performance after the announcement. The ratio of capital reduction has a negative (positive) influence on companies adopting capital reduction to write off accumulated losses (cash refund capital reduction), but does not affect companies adopting capital reduction by stock repurchases. The decision on capital reduction is not aimed at adjusting the company's capital. Moreover, investors do not react positively to additional expenditure on R&D for companies adopting capital reduction to write off accumulated losses. For companies adopting cash refund capital reduction, investors react more positively when directors and supervisors hold more outstanding shares and when the profit distribution right decreases. For companies adopting capital reduction by stock repurchases, market reaction tends to be more positive as the pledge ratio by directors and supervisors is lower.