本研究配合台灣制度，以模型推導方式研究IPO承銷機制選擇(競價拍賣與公開申購)之決定因素，並以台灣資料進行實證分析。本文考慮市場因素與投資人意見差異，以發行者之觀點進行分析。模型之預測為，當投資人意見差異程度較大、承銷規模較大、或是市場情況較佳時，發行者會選擇以競價拍賣銷售新股。 實證結果顯示，發行者於選擇承銷機制時，不僅考慮市場因素，亦會參考公司特性與發行特性，此結果與本模型之預測一致。本研究亦發現，台灣之競價拍賣制度，相較於公開申購方式，並無法更有效控制折價程度；如果發行者所選用的承銷方式，不適合市場情況、公司特性或發行特性，將會使公司的IPO承受較多的折價。 / This thesis develops and tests a theoretical rationale on the choice of IPO selling methods, discriminatory auctions versus fixed-price offerings, in Taiwan. We incorporate market conditions and investors’ divergence of opinions into the model from the issuer’s point of view. Our model predicts that when the extent of investors’ divergence of opinions is high, the amount in IPOs is large, or market conditions are hot, issuers will tend to use auctions. Our examination of issuers’ choice of IPO methods on the Taiwan’s IPOs shows that issuers condition the choice of IPO methods not only on prevailing market conditions, but also on firm/IPO characteristics. The results are consistent with our model. Finally, Taiwanese auction does not lead to less under-pricing than the fixed-price offering, but an issuer choosing a selling method with a higher degree of unfitting for firm/IPO characteristics and to market conditions will suffer more under-pricing.