以新上市股票 (IPOs) 市場的高度資訊不對稱環境，申購結果提供投資人決策參考的依 據。然而如此的跟隨行為，引述Welch (1992) 的資訊瀑布概念，可能令市場需求走向極 端。為檢測過度反應申購結果的情況，本研究提出評估IPOs 首日開盤交易導向的架構， 以區別申購結果對投資人決策形成的干預程度。實證顯示，相對於發行公司的基本條件， 投資人交易方向更加倚重申購需求。雖然上市初期績效表現與投資人跟隨方向一致，但 是針對申購需求交易基礎主導的樣本，其長期績效走勢卻切合過度反應的描述。另一方 面，檢視其他消息交易基礎引導首日開盤表現的樣本，則未觀察到過度反應的跡象。

In the initial public offerings (IPOs) market, an environment with high information asymmetry, subscription results provide concrete data that serve as a decision reference for investors. However, according to Welch (1992), who introduced the information cascade concept, this type of herd behavior can drive market demand to extremes. To examine investor overreactions to subscription results, this study proposed an assessment of the transaction-oriented framework of IPOs first-day openings to identify the intervening effect that subscription results have on investment decisions. Empirical evidence of transaction behavior shows that investors place greater emphasis on subscription results compared to the fundamental conditions of the issuing company. Although performance during the initial listing period was consistent with the investor herding direction, samples with subscription demand-guided transactions exhibited overreaction in the long term. By contrast, the phenomenon of overreaction was not observed in samples with first-day opening performances that were driven by transactions guided by other types of information.