我國股市的價格漲跌幅限制已逾三十年的歷史，主管機關維持此一機制的訴求是避免股價波動過於激烈、抑制投機行為。惟停板限制可能帶來的影響，除直覺上的其造成投資者持股風險指標扭曲等問題。經探究中亦歸結出（一）其被引為技術指標、（二）其引致財務風險指標扭曲等問題。
經探究GMM、Gibbs Sampler、與Two-Limit-Tobit Model模型的優劣。本研究發現一般使用的GMM估計量並非不偏，雖然可以藉修正增加其效率性，但仍無法藉以衡量各種的停板影響；Gibbs Sampler則過於依賴特定的先驗分佈，有可能因此而造成偏誤；而目前使用Tobit Model的文獻大都忽略停板限制對股價的影響力，據以產生的估計值亦附含偏誤。
本研究所採樣本期間為79年1月3日至84年10月9日，使用模型為Two-Limit-Tobit Model。為求嚴謹，在使用之前做資料的處理，並利用CAAR來驗證模型的正確性。實證顯示，漲跌停板的設立顯著改變投資人行為，在停板之前本研究發現存在技術指標與標準差統計量的向上偏誤，進而可能誤導實業界財務決策或學術研究結論。 / Thsi Study explores how price limits, which have remained in Taiwan Securities Exchange for over thirty years, affects both security price behavior and security risk indices. Its empirical results add to our understanding of the social costs and benefits of price limits. The SEC has been advocating the merits of price limits, emphasing that they help eliminating speculative trades and reducing security price volatility. In contrast, it remains a popular thought that price limits increase investors’holding costs and risks. To empirically examine the effects of price limits in Taiwan, this papers adopts Two-Limit-Tobit Model, together with CAAR as an indicator for specification validity. My test results lend support to the notion of (1).Technical Indicator Effect immediately before the price limits are hit; (2).Enhancement Effect the day after. Moreover, price limits contribute to bias in both systematic risk and total risk estimates (namely, β and σ) and thus distort investment decisions.
This Study also contributes to the contemporary literature by examining the merits and limitations of GMM, Gibbs Sampler, and Two-Limit-Tobit Model. GMM estimator is subject to statistical bias. One way may gain efficiency via adjustment. And yet GMM ahs pitfalls in directly measuring the price limit effects; The major limitation of the Gibbs Sampler is its reliance on specific prior information and it may lead to bias. And most of the papers adopting Tobit Model simply input the original data into the program, ignoring the fact that price limit may make the following day price data may be contaiminated.
| Identifer | oai:union.ndltd.org:CHENGCHI/B2002002760 |
| Creators | 黃健榮, Huang, Je Rome |
| Publisher | 國立政治大學 |
| Source Sets | National Chengchi University Libraries |
| Language | 中文 |
| Detected Language | English |
| Type | text |
| Rights | Copyright © nccu library on behalf of the copyright holders |
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