本研究將Fama and French (1993) 所建構的三因子模型 (three-factor model)改寫為縱橫平滑轉換迴歸模型 (panel smooth transition regression model, PSTR),並以代表投資人投資展望的恐慌指數 (volatility index, VIX) 及信用違約交換 (credit default swap, CDS) 為轉換變數,評估股價報酬的非線性路徑,以及三個隨時間變動的風險溢酬。樣本期間為2005年1月至2013年6月,研究對象為60家台灣上市(櫃)半導體公司。 實證結果顯示: 1. 股價報酬呈現非線性路徑,決定於轉換變數 (VIX 與CDS) 在各期的變動。 2. 在以VIX為轉換變數的PSTR模型下,股價報酬的市場風險溢酬是正的,且該貢獻隨VIX增加而下降;股價報酬的規模風險是正向的,且隨著VIX的上升而增加;股價報酬的價值風險溢酬是負的,且隨著VIX增加,此負向貢獻逐漸改善。因此, 三種風險溢酬隨時間而改變,而非如傳統的線性模型所述,是固定的。 3. 在以CDS為轉換變數的PSTR模型下,除了價值風險溢酬外,股價報酬的市場風險溢酬與規模風險溢酬仍呈現正向值。隨著CDS增加,市場風險溢酬與規模風險溢酬下降,而價值風險溢酬的負向效果減少。同理,此三種風險溢酬隨時間而改變,而非如傳統的線性模型所言,是固定的。
This thesis rewrites the three-factor model, developed by Fama and French (1993), as a panel smooth transition regression framework, and uses the volatility index (VIX) and credit default swap (CDS) as the transition variables in the framework, to evaluate the nonlinear path of stock returns and three time-varying risk premiums. Sample period spans from 2005:M1 to 2013:M6. Sample objects are 60 semiconductor companies listed on Taiwan Security Exchange Corporation. The empirical results can be summarized as follows: 1. The stock returns of semiconductor companies display a nonlinear path, depending on the changes of the VIX and CDS in each period. 2. For the PSTR model with VIX as the transition variable, the market premium of stock returns is positive and decreases with the increase in VIX; the size premium of stock returns is positive and increases with the increase in VIX, and the value premium of stock returns is negative and decreases with the increase in VIX. Thus, the three risk premiums are time-varying, not constant obtained from the traditional three-factor model. 3. For the PSTR model with CDS as the transition variable, the market premium of stock returns is positive and decreases with the increase in CDS; the size premium of stock returns is positive and decreases with the increase in CDS, and the value premium of stock returns is negative and decreases with the increase in CDS. Again, the three risk premiums are time-varying, not constant obtained from the traditional three-factor model.