價量關係一直是投資人觀察股市最直接的工具之一，但如何選擇適當的交易量變數卻是另一個難題。混合分配假說(Mixture of Distribution Hypothesis, MDH)認為交易量足以成為替代市場訊息流入的變數，但普通交易量的資訊成分過於複雜，並不能完全反應重大私有訊息的流入市場，在解釋價量關係上便稍顯不足。因此本文利用異常交易量(surprise volume)取代普通交易量，做為新的交易量變數，再加上GARCH-M的時序模型架構，試著解釋台灣股票市場的報酬波動。 但本文從台灣市場的實證中發現，只有未經過自我相關、季節性調整的異常交易量變數，才能與報酬率波動呈現顯著的正相關，但此交易量變數並無法大幅的降低波動程度的持續性。另外，不對稱的報酬波動效果(槓桿效果)在台灣市場上相當顯著，說明了負面衝擊的效應對於報酬波動的影響會來的較大，但股票加權指數報酬並不具有風險溢酬的特性。

台灣期貨交易所於92年1月20日推出到期採實物交割的股票選擇權契約，希望能提供市場更豐富、更多元的避險以及套利機能。然自股票選擇權推出以來，市場成交量並未如預期般蓬勃發展，便失去台灣期貨交易所推出股票選擇權之用意，不能使其充分發揮其多元之避險套利機能。多數人主觀認為，採用現金交割方式的衍生性金融商品容易受到人為操縱。一般而言，研究市場的人為操縱因子多以報酬波動率及到期日效應作為觀察指標，因此商品之交割方式與報酬波動率及到期日效應有一定之關聯。然而近來國外許多相關研究發現，採實物交割與現金交割，對股票選擇權的到期日效應並未產生差異，反而是透過結算制度的設計，可以有效降低人為操縱的機率。本研究旨在研究股票選擇權改採現金交割之可行性分析，研究到期日採現金交割是否就是增加人為操縱機率的主要因素，且到期日效應與到期交割方式是否又有絕對的關係？而根據文獻了解，到期日報酬波動率與受人為操縱之跡象是呈現正向關係。 / 因此本研究對指數期貨在到期日與非到期日時對指數現貨價格以及個股股價報酬波動率的影響程度進行實證分析，以報酬波動率之異常現象判斷是否有所謂到期日效應。 本研究實證結果指出，在台指期貨到期日報酬波動率和摩根台指期貨到期日的報酬波動率實證結果發現所有樣本在台指期貨到期日的報酬波動率都顯著高於摩根台指期貨到期日的報酬波動率。顯示台指期貨結算制度雖為到期日下一交易日開盤前十五分鐘個股成交量加權平均價結算，但並未有效降低異常報酬波動率的發生。根據國外研究結果發現，個股期貨能降低到期日效應之影響。此外，採實物交割與現金交割，對股票選擇權的到期日效應並未產生差異。為了降低到期日效應且提升市場的效率性，建議股票選擇權改為現金交割之外，尚可考慮開放個股期貨的交易。 / Taiwan Futures Exchange launched stock options on January 20, 2003, hoping to provide the market with more hedging and arbitraging opportunities. However, the trading volume does not grow as was expected. The low trading volume does not meet Taiwan Futures Exchange’s goal to provide the market with hedging and arbitraging mechanism. Most people think that derivatives applying cash settlement lead to manipulation. Researchers studying manipulations take the volatility of returns and expiration effects as the factors of their studies. However, some recent studies suggest applying cash settlement or physical settlement does not have much impact on expiration effects, while applying proper settlement system can reduce manipulation. / This research investigated the possibility of stock options applying cash settlement and examined the volatility of returns of stock indexes and stock prices during settlement and non-settlement days to determine if expiration effects exist. In this study, we found the volatilities of returns of all samples during TAIFEX settlement days are significantly higher than the volatilities of returns during SIMEX settlement days. All of our samples have significant higher volatilities of returns during TAIFEX settlement days and SIMEX settlement days except CMO, which does not have significant higher volatility of returns during SIMEX settlement days. Other researches point out the adopting of stock futures reduces the expiration effects. Furthermore, adopting cash settlement or physical settlement does have much impact on expiration effects. To decrease the expiration effect and to increase the effectiveness of the market, this study proposes the adoption of cash settlement and the launching of stock futures.