台灣早期有關系統風險（β）的研究皆指出β不能解釋台灣股票報酬的變異，故控尋更能解釋股票報酬的風險因素為本文的主要目的之一。 本研究分析民國71年7月至85年5月股票上市公司資料（排除金融、保險、及變更交易方式的公司）。因民國79年股價指數從2月的最高點12,495急遽下滑至10月的2,560，故分析上將79年度予以排除。在71年7月至78年12月的時段中，整體市場因素（RM-RF）不能解釋股票報酬的變異。此點發現與台灣早期研究的結論一致。其他變數顯著者僅有與規模有關的因素（SZSMB），或與負債比率有關的因素（DEHML），其中以 SZSMB的解釋能力最強。在民國80年1月至85年5月的時段中，所有模式中整體市場因素（ RM-RF）的係數皆顯著，並且是所有因素中最顯著者。這點發現與前時段（71年7月至78年12月）的結果有很大的不同。其他的變數顯著者，有代表成長機會的BMHML（與淨值市價比有關的因素）、EPHML（與益本比有關的因素）、或CPHML（與營運現金市價比有關的因素），及代表利率結構有關的風險因素TERM（與利率期間結構有關的風險溢酬）、或DFT（與利率違約風險有關的風險溢酬）。其中以（RM-RF）、EPHML、CPHML及TERM的風險組合最能解釋股票報酬的變異。 應用更完整的股票報酬解釋變數，探討股票報酬與盈餘間的關係，亦為本文主要目的之一。經分析以(1)各時段最能解釋股票報酬的因素組合為基礎，計算異常報酬；(2)單獨的以整體市場因素（RM-RF）為基礎計算異常報酬，然後再分別估出盈餘反應比較係數（ERC）比較之。結果顯示，以各時段最能顯著解釋股票報酬的因素組合為基礎的ERC為正的顯著，且其ERC大於只以整體市場因素（RM-RF）為基礎所算出的ERC。 另外，關於盈餘品質假說之測試，經以公司規模大小為虛擬變數放入迴歸式中，結果顯示，代表大公司的虛擬變數之係數時而為正，時而為負，且都不顯著，故盈餘品質假說未獲得支持。 再者，關於成長機會與ERC關係之測試，經以公司成長機會大小為虛擬變數放迴歸式中，結果顯示，代表成長機會的虛擬變數之系數時而為正，時而為負，且大都不顯著，故成長機會大的公司之ERC大於成長機會小的公司之ERC的假說，未獲得實證的支持。 / Earlier studies (Chen 1990; Chiu 1990; and Wang 1992) found that systematic risk (β) could not explain the variance of stock returns in Taiwan. The findings were inconsistent with the Capital Asset Pricing Model (CAPM). One of the major purposes of this paper is to examine the factors that have higher explanatory power of stock returns. To test the hypotheses, this study uses the data of Taiwanese listed companies covering the period from July 1982 to may 1996. The 1990 data are excluded because the stock market index climbed to a record high of 12,495 in February 1990 and then fell sharply to allow level of 2,560 in October 1990. The "crash" might cause structural changes in stock market, so the analyses are conducted separately for the periods before and after the crash, namely the prior-crash period (from July 1982 to December 1989) and the post-crash period (from January 1991 to May 1996). The empirical results show that for the prior-crash period the overall market factor (market returns minus risk free rate, RM-RF) can not explain the variance of stock returns. The findings are consistent with those of previous studies. However, we find that the factor-related to size (SZSMB) and the factor related to debt/equity ratio (DEHML) have significant association with stock returns. Furthermore, SZSMB has higher explanatory power. In contrast, the overall market factor is the most significant factor for the post-crash period. Other factors that are significant consisted of (1) proxies for growth opportunities, including book-to-market equity (BMHML), earnings/price ratio (EPHML), and cash flow/price ratio (CPHML), and (2) the factors related to interest structure, including term structure (TERM) and default risk (DFT). Among these factors, the set of RM-RF, EPHML, CPHML, and TERM explains the variance of stock returns most. Another purpose of this paper is to use the aforementioned findings to study the relationship between stock returns and earnings. The results show that the earnings response coefficients based on the most explanatory factor portfolio of each period are positive and significant, and are greater than those based on the traditional systematic risk (β). The tests for earnings quality hypothesis indicate that the coefficients of the dummy variable proxies for big companies are insignificant. The earnings quality hypothesis is not supported. The tests regarding the relationship between growth opportunities and earnings response coefficients show that the coefficients of the dummy variable proxies for high growth companies are unstable. The hypothesis that the earnings response coefficients of high growth companies are greater than those of low growth companies is not supported by empirical evidence.

已實現投資報酬率與無風險利率之差、被稱為超額報酬，而股票的預期報酬率超過無風險利率的部份則為股票風險溢酬，是許多資產評價模型的重要依據，例如資本資產定價模型。有不同的理論架構解釋說明風險溢酬值，例如；股票風險溢酬的迷思、短期損失的憎惡、生還存留因素和回歸與偏離平均值等等。 研究台灣股市的超額報酬與股票風險溢酬，有助投資大眾和企業理性面對股市的預期報酬和風險，對台股才有合理的期望報酬值。分析1967年迄2003年的台灣金融市場，計算過去37年長期的幾何平均年報酬率，以臺灣證券交易所發行量加權股價指數為台股市場報酬率，已實現台股實質年報酬率為6.71%。無風險報酬率使用第一銀行的一年期定期存款利率，實質台幣存款年利率為3.07%，消費者物價指數年增率則為4.80%。以年資料計算的台股實質超額報酬，算術和幾何值分別為12.48%和3.63%(年)，計算月資料算術平均和幾何平均值分別為0.77%和0.25%(月)。過去37年長期的台股超額報酬現象未較歐美市場的情況更加明顯，也比一般市場的預期報酬率低。 因資料取得的限制、台股的理論超額報酬方面，1991年迄2003年的近十三年來，經固定股利成長模式和盈餘成長模式的兩種計算方式，台股的實質超額報酬分別為 0.6%和-4.3%，此時期台股的投資報酬率比起台幣存款並不突出、且是低超額報酬。同期的已實現的實質超額報酬值；算術平均1.69%和幾何平均-3.35%。評估目前台股風險溢酬，將十分接近過去37年長期歷史資料得到的超額報酬數值，算術年均值為12.48%(年)和0.77%(月)，幾何平均分別為3.63%(年)和0.25%(月)，低風險溢酬是當前台灣股票市場的一般現象。 / The difference between the observed historical investment return and the risk-free interest rate is the excess return. The equity risk premium, ERP is the expected rate of return on the aggregate stock market in excess of the rate of risk-free security. ERP is one of important factor of many asset-pricing models, including Capital Asset Pricing Model, CAPM. There were many theories and factors to explain the equity risk premium; equity premium puzzle, myopic loss aversion, survivorship bias, mean reversion & aversion and etc. Studying the value of Taiwan equity excess return and risk premium is fundamental for investors and institutions evaluating the expected market investment return and risk. Analyzing the data from year 1967 to 2003 for thirty-seven years long holding period, Taiwan Stock Exchange Capitalization Weighted Stock Index as Taiwan stock market return, the realized real return was 6.71%. One-year bank time deposit rate as NT dollars risk-free asset rate and real interest rate was 3.07% and consumer price index, CPI annual growth rate was 4.80%. The historical real yearly excess return was 12.45% for arithmetic mean and 3.63% geometric mean; the historical real monthly excess return was 0.77% for arithmetic mean and 0.25% geometric mean. Taiwan realized equity excess returns were not higher than the returns in the developed countries and were also lower than the market's expectation. Due to the limits of available data, the theoretical equity excess returns that were calculated on two theoretical models; Constant Growth Dividend Discount Model (dividend yield model) and earnings yield model were 0.6% and -4.3% from year 1991 to year 2003. Comparing the same period of historical realized excess returns of 1.69% for arithmetic mean and -3.35% geometric mean, Taiwan stock market returns were not spectacular. The current equity risk premium of Taiwan stock market is low and should be near the level of the long historical realized equity excess return.