論文摘要 我國新版承銷制度的要旨，在藉由市場供需法則與法人專業判斷的兩大機能運作，來改善我國過去股市中新上市股票蜜月期的種種不合理現象。本研究目的在實証這項制度立意，是否經過四年多來的實際運行，得以實現。 本研究從兩方面展開；首先，構建迴歸模式，並透過不同樣本分群的處理，找出在全體樣本不分組、非競價拍賣組、競價拍賣組等三群樣本，其各自影響承銷價合理性的因素，再以實証結果分析其成因。其次，針對法人參與競價拍賣的競標過程加以分析，以法人投標率代表其參與市場的深度，以法人得標佔投標百分比代表其參與競價的積極程度。利用T檢定檢視法人和一般投資人在競價市場中究竟由誰主導價格的形成，以及何者在競價過程中態度較為積極。 經實証研究發現，在全體樣本和非競價拍賣組中，負債比低的公司其承銷價格越合理，而現金股利宣告越多、蜜月期正處於市場狂飆期、並為新興電子業者，其承銷價格越不合理。但是同樣的模式並不適用於競價拍賣組的承銷價格合理性推論；因此可知新版承銷制度的施行的確對於承銷價格合理性的因素有所影響。至於對法人參與競價拍賣制的實証結果發現，機構投資人參與市場的深度尚不及一般投資大眾，且其競價的態度亦較保守，不過法人的參與市場的確有助於更合理的承銷價格的形成。 最後，本研究對新版承銷制度的施行提出建議，除了誘導法人更積極參與市場，協助合理承銷價格的形成之外，更應把焦點延伸至股票上市後的股價穩定與維持，而不只是侷限在上市時單一時點的股價而已。以上兩點建議可供主管機關作為制訂相關決策時之參考。 / Abstract The main object of the new systems of underwriting in Taiwan, is to improve the unreasonable price performance during the honeymoon period by market decision and professional judgements of the institution investors. The purpose of this research is to exam whether the object if the auction procedure has been realized after the four years execution. Hence, the regression models are built, and the samples are classified into three groups: auction group、non-auction group, and the total sample group, to individually test the implicated factors that will influence the reasonability of the price performance on the common stock new issued under the three treatments of sample groups. Then, the behaviors of the institution investors in the competitive bidding process are analyzed to test the role who play in forming the price. According to this study, it is found that in the total sample group and the non-auction group, the company with lower liability ratio will lead to a more reasonable IPOs underpricing; and the one with higher cash dividends、the new issued stock of which published when the market is in the bull position, and belonged to electronic and information industry, will lead to a unreasonable underpricing.but the same model used to expect the reasonability in the non-auction group and the total sample group is not subject to the auction group, according to this we can draw a conclusion that the new systems of the underwriting, auction procedure, do effect the reasonability of the underpricing. As to the research on the behavior of the institution investors, it is found that they are less positive than the other investors in the price forming process, but it is true that the participation of the professional institution investors helps in forming more reasonable underpricing. According to the conclusion made above, this study command that in addition to promoting institution investors to participate the market positively, we should also focus on the price stability and maintenance after IPOs rather than the price formed at the time the stock first published. The results of this research can be taken into consideration when making relative decisions.