探討公司治理對新上市櫃公司股票初期報酬與長期績效表現之影響

Abstract

本研究以台灣新上市（櫃）公司為對象，實證探討公司治理因素對於股票初次公開發行(initial public offerings，IPOs)時對承銷價、初期報酬、以及長期績效表現的關聯性研究。傳統上，新上市（櫃）股有正的初期報酬多被認為是基於資訊不對稱及訊息傳遞的問題所導致；但本研究從公司治理的角度來檢視其對公司價值的影響，主要的推論是當公司治理機制愈佳，預期經理人正的誘因效果愈大，負的侵佔效果則愈小，提昇公司資訊透明度，且公司之會計盈餘資訊將愈充足，則公司之財務報表可信度隨之提高，也反映在公司的股票價值，因此當公司初次公開發行時，愈有能力與承銷商議價，且在上市（櫃）後，其初始報酬也愈高，同時其長期績效表現也愈佳。 本研究引用La Porta等人(2002)及Claessens等人(2002)正的誘因效果與負的侵佔效果，以及Fan和Wong(2002)之會計盈餘的資訊內涵，推論公司治理機制會影響承銷商與投資者對於IPOs公司價值的判斷。且採用La Porta (2002) 所提出股東對公司之控制權(投票權)與現金流量權間之偏離程度做為衡量公司治理績效的因子，及Purnanandam & Swaminathan (2002) 之承銷價倍數（P/V值）來做衡量公司承銷價格的指標。實證以2001年至2004年間共392家台灣IPOs上市（櫃）公司為樣本，驗證顯示，當控制股東之控制權與現金流量權的偏離幅度較低，代表公司治理機制愈佳時，其IPOs承銷價倍數愈高（代表承銷價格訂得較高）；而上市之後初期的股價表現也愈好，因此漲停板的天數愈多。再者在長期績效表現上，公司治理較佳的IPOs公司，其三年相對於配對樣本的財富指標（wealth relative）較佳（但未達顯著水準），而至少未有長期股價表現較差的現象；亦即初期的股價表現並非投資人過度樂觀所致，公司治理的好壞仍具有影響力。

Many IPOs literatures document that the mean initial return of IPOs is significantly positive. But what caused the positive initial return? Underpricing is the most popular explanation. Some studies emphasized that the main reason for issuing firms to underprice their stocks is asymmetric information. However, among different inferences, we include that the initial return is composed of two parts, one is the pricing of offer price and the other is the after-market reaction of investors. Referring to the findings of La Porta et al. (2002), Claessens et al. (2002), and Fan and Wong (2002), this thesis will examine if the corporate governance mechanism will influence IPOs offer price and after-market price performance. The better the corporate governance is, the higher firm value will be. Therefore, the issuing firm has more negotiating ability to set a higher offer price. On the other hand, the better the corporate governance is, the more earnings informativeness will be. This will enhance the credibility of financial statements and reduce the degree of asymmetric information. Meanwhile, investors would like to pay higher price buying the stock and lead to a better after-market performance. In a sample of 392 Taiwan IPO firms from 2001 to 2004, we trace the controlling shareholders of firms and calculate their control right and cash flow right, of which could find that better corporate governance of issuing firms result in higher offer price and better after-market performance. As to the long-run performance, an IPO firm with better corporate governance would have better performance but not so significant. Consequently, we can conclude that corporate governance does affect IPOs offer price and after-market price performance.