民國89年6月我國立法院通過公司買回本公司股份法案，庫藏股制度正式實施，本論文之主要目的在利用市場資料，探析我國上市（櫃）公司買回庫藏股之市場反應及其資訊內涵。本研究以民國89年8月至90年2月間公告買回庫藏股之公司，及依同產業及相似買回比率配對之公司組成研究樣本，首先採事件研究法探討庫藏股法令制定與修正之相關事件日市場反應，以及宣告買回庫藏股之市場反應及其影響因素，並以關聯性研究法實證宣告買回庫藏股市場反應之資訊內涵及買回目的之影響因素。 　　在市場反應議題之主要研究發現為：（1）在庫藏股立法初期、降低操作困難度及解除指撥特別盈餘公積規定等有助於庫藏股制度之推行:投資人有正面顯著之回應；（2）宣告買回樣本之股票累積異常報酬顯著高於未宣告買回之樣本；（3）維護股東權益買回目的者之股票累積異常報酬顯著高於轉讓與員工為目的者；（4）宣告買回比率愈多市場反應愈佳；及 （5）價格回升之公司其實際執行率較低。 　　在資訊內涵議題之主要實證結果顯示，我國宣告買回庫藏股之資訊本質顯著支持企業價值低估假說，公司價值被低估程度愈高，宣告買回庫藏股之市場反應愈大。至於自由現金流量假說、資本結構調整假說及剝奪債權人假說則無法解釋我國宣告買回庫藏股之資訊內涵。在買回庫藏股目的之實證結果顯示，高淨值市價比之公司偏向以維護股東權益為買回目的，而研發活動愈密集之公司傾向以轉讓與員工為買回目的。 / The enactment of Article 28-2 of the Securities and Exchange Act on June 30, 2000 allows firms listed in Taiwan Stock Exchange (TSE) and Over-The-Counter (OTC) to repurchase their owner shares under certain conditions. Based on the use of a control sample design and firms listed in TSE and OTC over the period of August 2000 to February 2001, this research examines the market reaction to various events including: (1) the enactment of the law and amendment of regulations with regard to share buyback, (2) the announcement of repurchase ratio and purpose, and (3) the disclosure of actual buyback ratio. In addition, this study tests hypotheses underlying market reaction around the announcement of share repurchases in the open market. 　　The empirical findings indicate that (1) market reacts favorably to establishment of stock repurchases system, (2) cumulative abnormal return (CAR) for the share buyback announcement sample is found to be greater than that for the control sample, (3) CAR for firms aimed at retaining the interests of equity shareholders as buyback purpose is found to be higher than that for transfer to employees as purpose, (4) the higher the announced buyback ratio, the greater the market reaction, and (5) the actual buyback ratio is less for firms with stock price recovery. 　　This study also finds undervaluation hypothesis explains the market reaction on the announcement date. With respect to the disclosure of share buyback purposes, the analysis indicates that firms with higher book-to-market ratio are more likely to announce protecting shareholders equity as the buyback purpose, whilst firms with higher demand for research & development activities are prone to announce transfer shares to their employees as the buyback purpose.

我國庫藏股制度於民國八十九年開始實施，當上市櫃公司宣告買回庫藏股後，造成了公司資產的重分配，其股東、債權人等利害關係人會以預期心理來評估自身權益所受到的影響，並將其反應在所要求的必要報酬率上，因此公司對股東所負擔的權益資金成本及對債權人所負擔的負債資金成本都將產生變動。 當公司宣告買回庫藏股後，實證結果顯示：(1)其負債資金成本將上升，而權益資金成本將會下降。(2)預定買回股份佔資本比愈大時，其負債資金成本增加愈多。(3)買回前獲利能力之不同，並未發現其會對宣告買回公司之負債資金成本有顯著影響。(4)依目的三買回將使該公司負債資金成本增加數小於依目的一或目的二買回之負債資金成本增加數、並使權益資金成本減少數大於依目的一或目的二買回之權益資金成本減少數。(5)公司內部人持股比率於宣告前一年淨增加愈多則權益資金成本降低程度愈大。(6)資訊愈對稱的公司其權益資金成本下降的程度愈少。 / Share repurchase system was formally implemented in Taiwan in 2000 , when the TSEC & OTC listed companies announce that they will repurchase shares , it changes the composition of assets held by the firm , revising the ownership proportions of each of their shareholders and interests of each of their creditors. Thus, their cost of equity capital and debt capital may change . When companies announce to repurchase shares , results show that : (1)their cost of debt capital will increase and their cost of equity capital will decrease. (2)the more percentage of shares companies expect to repurchase , the more their cost of debt capital increase. (3)the different profitability before announcement has no significant effect to companies’ cost of debt capital. (4)repurchase in order to conserve companies’ credibility and shareholders’ equity will increase less cost of debt capital and decrease more cost of equity capital than that in order to reach other two purposes .(5) the more increase of percentage of shares companies’ insiders’ hold before announce, the more their cost of equity capital decrease. (6) the more symmetrical information companies obtain , the less their cost of equity capital decrease.

本研究探討國內上市櫃公司庫藏股減資及現金減資宣告效果之比較。研究台灣2006年1月至2010年2月底之間進行庫藏股減資及現金減資的上市櫃公司，分別以事件研究法、多元迴歸分析（Multiple Regression Analysis）及多元名義羅吉特迴歸（Multinomial Logistic Regression）探討庫藏股減資及現金減資兩組樣本之宣告效果及影響宣告效果的因子，並進一步探究影響減資政策選擇的因素。本研究之實證結果發現：1.公司宣告庫藏股減資及現金減資在事件日當天皆具有顯著的正向宣告效果。2.公司宣告庫藏股減資與現金減資之間的累積異常報酬率無著顯著差異。3.以多元迴歸分析探討影響庫藏股減資及現金減資之間累積異常報酬率的因素，結果顯示減資比率顯著地影響累積異常報酬率，其餘本研究選取的公司規模、股價淨值比、負債比率、自由現金流量比率等解釋變數，無法顯著地影響累積異常報酬率。4.以多元名義羅吉特迴歸檢驗不同的解釋變數會造成公司傾向進行庫藏股減資或現金減資的減資政策，結果顯示規模愈大、股價淨值比愈高、自由現金流量比率高、減資比率高的公司，傾向使用現金減資；而負債比率高的公司，傾向使用庫藏股減資。

本論文從員工認股權制度之意義和功能出發，了解該制度之基本構成要件、優點，實施該制對公司、員工、股東三方之影響，以及探討員工認股權契約之性質及內容。有關員工認股權制度之基本規範，包括：認股權人之資格條件、決策機關、認股價格、認股條件、等待期間和權利行使期間等本文亦逐一探討，並以我國制度為出發點，參考外國立法例上之相關規定，探討這些規範之妥適性。 員工認股權憑證之發行須依處理準則之規定為之，惟員工認股權憑證不得轉讓，其性質已和證券交易法上之其他有價證券有所差異，且員工認股權憑證之發行對象為公司員工，發行目的係作為員工薪酬，也和其他有價證券以投資大眾為對象、以募集資金為目的不同，基於這些性質上之差異，證交法介入之需要性已然降低，則員工認股權憑證是否有依循處理準則發行之必要性？ 美、日二國公司法中有關認股權之規定並不多，而賦予企業依其需要設計適合該公司之制度，但另於稅法中針對符合特定條件之認股權予以租稅上之優惠。反觀我國卻在處理準則中對於員工認股權制度之作了完整之規範，此種方式是否壓縮了員工認股權制度之彈性？ 員工認股權憑證發展自認股權憑證，但基於作為對員工長期性之誘因報酬制度，在特性上已和認股權憑證有所差異，本文將討論二者之異同。同時也探討員工認股權憑證和認購（售）權證、選擇權契約等制度之差異。除了新引進之員工認股權制度外，公司法上尚有員工分紅制度、員工分紅入股制度、員工新股優先承購權等其他員工激勵或員工持股制度，這些制度和員工認股權制度有那些差異及其適用時機本文也將一一討論。

庫藏股制度於國外已經行之有年，特別是美國，早在1960年代即有庫藏股交易。我國上市上櫃股票可合法買回自己公司股票制度始於2000年所通過的上市上櫃公司買回本公司股份辦法，除了希望藉以提振東南亞金融危機中不振的股市表現，也賦予企業多一種能向投資人傳遞訊息的管道。本研究基於股票買回的各項假說，希望探究公司股票買回宣告的動機還有事件宣告後對於公司股價的影響效果，最後並檢視公司的宣告決策是否會受到前次購回宣告的表現所影響。 在假說驗證方面，以2000至2004年上市公司832家、上櫃公司236家曾經宣告買回自家股票的公司為研究樣本，輔以選出與買回樣本同時間的相同數量「未買回樣本」，透過1-way ANOVA測試與鑑別分析探討影響公司宣告股票買回的因素符合哪些假說的推論結果。此外，依據各項假說，進ㄧ步利用1-way ANOVA測試和複迴歸分析找出與公司事件宣告後股價異常報酬率之間的關係，接著以1-way ANOVA檢視最後一部份研究主題。經由上述的實證分析，本研究獲得以下主要結論： 1.公司買回自家的股票平均而言對於股價有正面的影響效果。 2.以上市公司而言，影響公司宣告股票買回的假說包括了：自由現金流量假說、個人所得稅節稅假說與財務槓桿假說。以上櫃公司而言則包括：自由現金流量假說、個人所得稅節稅假說與資訊信號假說。 3.以上市公司而言，股票買回宣告後，股價的正向異常報酬與：自由現金流量假說、管理者的誘因假說呈現相關關係。上櫃公司則包括：自由現金流量假說。 4.本次是否再度宣告股票買回會受前次買回的正向累積異常報酬率所影響。 / Stock price reactions on stock repurchase announcements among publicly traded corporations have been widely studied over 40 years in United States. Several hypothesizes were established and provide logical reasons for why corporations buy back their own stocks. References show large proportion of positive effect on post-announcement stock price after stock repurchase announcements from empirical researches. It is since 2000 that corporations are allowed to repurchase their own stocks legally in Taiwan. Although many efforts were put in surveying the post-announcement stock price reactions, few focused on examining how corporations’ repurchase decision would be influenced by different hypothesizes. Moreover, whether or not previous repurchase outcome may affect future repurchase judgments met contradict conclusion from recent studies. This research aims on exploring the two main topics which form 7 hypothesize. Data collecting from Taiwan Economic Journal (TEJ) database, Commercial Times and Economic Daily News contains publicly traded corporations had ever made stock repurchase announcement except financial and government institutions. The period of the study was from Aug. 6, 2000 to Jul. 31, 2004 and total number of announced corporations included was 832 listed on the Taiwan Security Exchange with 236 listed on the OTC separately. Hypothesis 1 to 6 were tested both from individual model using 1-way ANOVA Analysis and integrated model using Discriminate Analysis on Hypothesis 1 to 5, Event Study Analysis on Hypothesis 6. Hypothesis 7 was also verified with 1-way ANOVA Analysis. The empirical results show supports in several hypothesize which reflect corporations did concern free cash flow amount, leverage level, stock underpriced and dividend payout level issues when making repurchase announcement. The stock price after announcement has certain degree of moving correlation toward the same direction as free cash flow level and managerial stockholding level. Finally, previous repurchase outcome was found holding opposite relation with future repurchase judgments.