Agency theory, which discusses the conflict between agent and principle, was developed by Jensen and Meckling in 1976. Owing to the separation of ownership and management, shareholders and management authority have agency relationship. The one reason that shareholder hand in company affairs to management authority is that management authority has better management ability. Another reason is that shareholder cannot handle by himself for some reasons and must hand in to other people. Management authority has the advantage of information and they also seek for their own interest. But these behaviors may damage shareholder¡¦s right and agency problems occur in the situation. Agency problems occur not only between shareholder and management authority but also between management authority and lender in a company with debt. Shareholders often supervise management authority more strictly and make more rules to confine management authority in order to reduce agency problem or protect their own interest. But these actions disturb management authority when management authority is full of ambitions and endeavor. If agency problems between shareholder and management authority cannot be solved properly, it will make company operate abnormally and damage the nation¡¦s economic further. On the contrary earning forecast can reduce information asymmetry. If management authority can disclose earning forecast voluntarily, it is helpful to reduce the agency problem and the information asymmetry between shareholder and management authority. The article assumes management authority disclose earning forecast voluntarily in order to get shareholder and debtor¡¦s trust in this point of view and use firm size¡Bfree cash flow¡Bleverage as the proxy of agency cost. In this research we find that the more debt the company have, the higher voluntarily the company discloses earning forecast. It is the same as we expect. But free cast flow is not significant. When firm size is bigger, the management authority is less voluntary to disclose earning forecast. The result is contrary to the view of agency problem.

本論文的目的，在探討財務分析師盈餘預測修正的決策過程。因為財務分析師可以說是市場上的專業分析者，故其決策過程特別讓人感到興趣。藉著相關性的迴歸分析，將讓我們了解到分析師的盈餘預測修正可能受到修正前何種事件的影響。 　　本研究依據文獻探討及延伸發展出四個可能會影響分析師盈餘預測正修正方向及幅度的變數，分別是分析師預測修正期間（兩次預測的間隔期）的累積股票報酬率、未預期到的公司管理當局盈餘預測、未預期到的公司期中盈餘以及未預期到的公司期中銷貨。研究期間是從民國七十九年至八十二年，研究的對象則是「財訊」月刊內的研究分析人員（財務分析師）在月刊上所刊載的上市公司盈餘預測。 　　實證結果顯示，在對分析師預測修正的幅度上，以未預期的公司管理當局盈餘預測及未預期的公司期中盈餘兩者有影響力，且如假說預期般地與因變數呈現正相關。在對分析師預測修正的方向上，則四個自變數皆有影響能力，其中前三個自變數與分析師預測修正方向呈現正相關，但最後一個變數則與假說相反地呈現負相關。 　　本研究結果背後可能的原因探討如下：公司管理當局發佈的盈餘預測和公司期中盈餘兩者對分析師的盈餘預測修正方向與幅度上皆有正向影響力，可能意味著此二種資訊的品質具參考性，故才值得專業分析師的青睞。而分析師預測修正期間的累積股票報酬率只對盈餘預測修正方向上有正向的解釋力，暗示著分析師在預測修正時並未完全重視此項資訊。至於公司的未預期期中銷貨對分析師的盈餘預測修正方向上有負向的影響作用，則此異常現象留待後續研究者進一步的探討與測試。

本研究以I/B/E/S中2004至2005年所有美國公司為樣本，依財務分析師盈餘預測值與所有財務分析師盈餘預測平均值之差異程度，將財務分析師分類為大膽或膽怯的財務分析師，並依財務分析師盈餘預測發布之時點將財務分析師分類為領導型或從眾型財務分析師。針對財務分析師盈餘預測行為大膽及領導特性，探討時效性領導型財務分析師之盈餘預測是否會較大膽，並進一步研究大膽的財務分析師其盈餘預測準確度是否較高，以及時效性之領導型財務分析師其盈餘預測準確度是否較高。 研究結果發現時效性之領導型財務分析師其盈餘預測行為會較大膽，但大膽的財務分析師其盈餘預測準確度較低，且時效性之領導型財務分析師其盈餘預測準確度並未出現較高的現象。 / Security analysts can be characterized as bold or herding based on the absolute distance between their earnings forecasts and the consensus forecast. Security analysts can also be classified as lead or following based on the timeliness of their earnings forecasts. Based on I/B/E/S annual earnings forecasts of all American companies during the period of 2004-2005, this study addresses the association between bold and lead and the relation between bold forecast and forecast accuracy. In addition, the relation between lead forecast and forecast accuracy is investigated as well. It is shown that lead analysts are bolder than following analysts and boldness likelihood increases with the frequency of analysts’ forecast and declines with the analysts’ prior accuracy. Further, bold analysts’ earnings forecasts are less accurate than herding analysts’ and lead analysts’ earnings forecasts are less accurate than following analysts.

本研究旨在探討管理當局自願性盈餘預測與權益資金成本之關聯性，檢視管理當局發布盈餘預測頻率之影響是否反應於權益資金成本上，並進一步檢視管理當局之聲譽是否為影響權益資金成本的因素之一。 在本研究的實證分析結果中，發現管理當局發布自願性盈餘預測之頻率與權益資金成本呈顯著負相關，表示管理當局發布盈餘預測的次數越多時，權益資金成本越低。 在管理當局聲譽對於權益資金成本的影響，本研究實證分析結果發現，管理當局之聲譽與權益資金成本亦呈顯著負相關，管理當局聲譽以管理當局預測誤差和分析師預測誤差來衡量，當管理當局的盈餘預測誤差小於分析師盈餘預測誤差時，投資人認為管理當局對盈餘的預測有效且值得信賴，此時管理當局聲譽提高，投資人認為取得有用的資訊，進而降低企業權益資金成本。 / The primary objective of this thesis is to explore whether the frequency of management forecasts is related to the cost of equity capital. In addition, I further examine whether the association is stronger when management has better reputation. Basing on a sample of S&P 500 listed firms during 2000-2009, I find that, consistent with my prediction, cost of firm’s equity capital decreases with the frequency of management earning forecasts after controlling for other determinants well-documented to be related to cost of equity capital. Second, I find that cost of equity capital is negatively related to the reputation of management; however, I do not find that the association between cost of equity capital and the frequency of management systematically vary with the reputation of management.