This essay investigates how realized variance affects the GARCH-models (GARCH, EGARCH, GJRGARCH) when added as an external regressor. The GARCH models are estimated with three different distributions; Normal-, Student’s t- and Normal inverse gaussian distribution. The results are ambiguous - the models with realized variance improves the model fit, but when applied to forecasting, the models with realized variance are performing similar Value at Risk predictions compared to the models without realized variance.

Magister Scientiae - MSc / We investigate some simulation-based approaches for the valuing of the employee stock options. The mathematical models that deal with valuation of such options include the work of Jennergren and Naeslund [L.P Jennergren and B. Naeslund, A comment on valuation of executive stock options and the FASB proposal, Accounting Review 68 (1993) 179-183]. They used the Black and Scholes [F. Black and M. Scholes, The pricing of options and corporate liabilities, Journal of Political Economy 81(1973) 637-659] and extended partial differential equation for an option that includes the early exercise. Some other major relevant works to this mini thesis are Hemmer et al. [T Hemmer, S. Matsunaga and T Shevlin, The influence of risk diversification on the early exercise of employee stock options by executive officers, Journal of Accounting and Economics 21(1) (1996) 45-68] and Baril et al. [C. Baril, L. Betancourt, J. Briggs, Valuing employee stock options under SFAS 123 R using the Black-Scholes-Merton and lattice model approaches, Journal of Accounting Education 25 (1-2) (2007) 88-101]. The underlying assets are studied under the GARCH (generalized autoregressive conditional heteroskedasticity) effects. Particular emphasis is made on the American style employee stock options. / South Africa

本文主要是研究浮動匯率期間匯率波動對出口產業的影響。一般認為，匯率波動匯會使出口廠商的利潤風險增加，所以波動對於出口量的影響是為負的效果。不過，由於許多國外的研究的結果並不一定支持這種看法。本文針對台灣1984到1995年的資料進行實證研究，並且分別就不同出口產業對匯率波動的反應程度做討論，包括紡織類，塑膠化學類，電子類，機械類及基本金屬類五種產業，主要分為兩個架構分析： 　　（一）衡量匯率波動因子：對於匯率波動的衡量分成兩種方法：一種是以過去匯率變動的方式來衡量，另一種是以本期匯率預測的誤差來衡量，大部份的文獻都是採用前者。在此，為了將廠商事先避險的行為引入，所以採用後者的方法，將預測到的波動與未預測到的波動分離開來。 　　（二）匯率波動對各產業出口量的影響：將所有符合I(1)性質的變數用Johansen的方法做長期共整合關析的估計，再利用Granger Representation Theorem導出短期誤差修正模型，並將符合I(0)性質的波動因子引入模型當中，以便觀察匯率波動對出口量的影響。結果發現，各產業的出口量皆與匯率波動間存在明顯的負相關，其中以電子產業的影響最顯著，紡織類次之，基本金屬類影響最小，根據產品的特性分析可發現：當出口競爭愈激烈者，或是出口彈性愈大者，相對來講，會對匯率波動的反應較敏感。

本研究主要探討幾個廣受市場投資人所使用的波動度預測模型，如歷史波動度法、指數加權移動平均法、GARCH、EGARCH以及隱含波度，另外再考慮近年才被學者提出的RLS模型與A-RLS模型，一同比較它們對於台灣市場波動度的預估能力，並擇一最優者，作為從事波動度交易的訊號依據。本文在進行波動度交易之實證，主要是利用選擇權與期貨組合、選擇權與delta期貨組合、跨式交易策略與勒式交易策略等四種廣為波動度交易者使用之波動度交易策略，進而比較它們在樣本外的交易績效。本波動度預測的實證發現，樣本內的預測能力，是以GARCH和RLS模型最佳，而樣本外的預估能力，則是GARCH表現最好。另外，波動度交易的驗證結果顯示，若持有至次一交易日即平倉，勒式交易策略於買進波動度時會有最高的績效，而當放空波動度時，則是跨式交易策略會有最佳的表現。

Cette thèse de doctorat propose un modèle d'évaluation, des options avec sauts, volatilité et taux d'intérêt stochastiques, dont la solution analytique généralise les formules de Black & Scholes (1973), Heston (1993), Bates (1996) et Bakshi, Cao & Chen (1997). Après avoir exploré la capacité des schémas GARCH à modéliser la structure par terme de la volatilité de l'indice S&P500 sur le CBOE, la volatilité stochastique devient le coeur probabiliste du paradigme d'incomplétude des marchés. Mais faire de la volatilité stochastique ne permet pas encore de capturer les grandes valeurs de kurtosis pour les options courtes. Le problème leptokurtique est alors résolu en adoptant une classe de distributions générées par des processus de diffusion à sauts. L'effet d'une fréquence aléatoire des sauts poissonniens dans le processus des rentabilités est examiné sur le CBOE. Par ailleurs, l'auteur propose une extension académique du modèle en présence de dividendes stochastiques.

<p>The work is focused on the Value at Risk and the Expected Shortfallcalculation. We assume the returns to be based on two pillars - the white noise and the stochastic volatility. We assume that the white noise follows the NIG distribution and the volatility is modeled using the nGARCH, NIG-GARCH, tGARCH and the non-parametric method. We apply the models into the stocks of three Banks of the Nordic market. We consider the daily and the intraday returns with the frequencies 5, 10, 20 and 30 minutes. We calculate the one step ahead VaR and ES for the daily and the intraday data. We use the Kupiec test and the Markov test to assess the correctness of the models. We also provide a new concept of improving the daily VaR calculation by using the high frequency returns. The results show that the intraday data can be used to the one step ahead VaR and the ES calculation. The comparison of the VaR for the end of the following trading day calculated on the basis of the daily returns and the one computed using the high frequency returns shows that using the intraday data can improve the VaR outcomes.</p>

The work is focused on the Value at Risk and the Expected Shortfallcalculation. We assume the returns to be based on two pillars - the white noise and the stochastic volatility. We assume that the white noise follows the NIG distribution and the volatility is modeled using the nGARCH, NIG-GARCH, tGARCH and the non-parametric method. We apply the models into the stocks of three Banks of the Nordic market. We consider the daily and the intraday returns with the frequencies 5, 10, 20 and 30 minutes. We calculate the one step ahead VaR and ES for the daily and the intraday data. We use the Kupiec test and the Markov test to assess the correctness of the models. We also provide a new concept of improving the daily VaR calculation by using the high frequency returns. The results show that the intraday data can be used to the one step ahead VaR and the ES calculation. The comparison of the VaR for the end of the following trading day calculated on the basis of the daily returns and the one computed using the high frequency returns shows that using the intraday data can improve the VaR outcomes.

本研究以日本央行干預日圓匯率對新台幣匯率的波及效果為研究主題，選擇樣本期間為1999年1月5日至2003年12月31日之日資料做實證分析。本研究選擇日本央行干預外滙的貨幣數量、新台幣與日圓間前一日及前二日的匯率變動率、日本國定假日及日本重大經濟政策訊息為自變數，分析對因變數，也就是新台幣與日圓間匯率變動率有何影響。我們分別採用最小平方法(OLS)迴歸分析與一般化自我迴歸條件異質變異數GARCH(1,1)模型來進行分析，並發現GARCH(1,1)模型在估計上優於最小平方法(OLS) 迴歸分析；另外我們的結果也證實日本央行干預日圓與美元間匯率，在日圓外匯市場大量購買外匯，確實會對新台幣與日圓間匯率變動率造成影響，亦其的確對新台幣與日圓間匯率變動程度有波及效果。 一直以來，國內有關央行干預行為的文獻中，大多探討台灣中央銀行的干預行為，對新台幣與美元間匯率變動的影響，較少有文獻在討論當日本央行透過干預日圓外匯市場，意圖使日圓相對於美元貶值時，新台幣與日圓間匯率的變動程度會因此受到波及。而本文實證研究發現，日本央行在干預日圓匯率時，的確會對新台幣與日圓間的匯率變動率造成影響，也就是說，日本中央銀行干預日圓匯率對新台幣匯率的波及效果是存在的，這對未來在估計新台幣與日圓間匯率變動時，將更能精確的估計新台幣與日圓間匯率變動的程度。 關鍵詞:匯率干預(exchange rate intervention)、日本央行(Japan Central Bank)、 最小平方法(OLS)、一般化自我迴歸條件異質變異數(GARCH)

This dissertation contains three independent essays relating energy economics. The first essay investigates price asymmetry of diesel in South Korea by using the error correction model. Analyzing weekly market prices in the pass-through of crude oil, this model shows asymmetric price response does not exist at the upstream market but at the downstream market. Since time-variant residuals are found by the specified models for both weekly and daily retail prices at the downstream level, these models are implemented by a Generalized Autoregressive Conditional Heteroskedasticity (GARCH) process. The estimated results reveal that retail prices increase fast in the rise of crude oil prices but decrease slowly in the fall of those. Surprisingly, retail prices rarely respond to changes of crude oil prices for the first five days. Based on collusive behaviors of retailers, this price asymmetry in Korea diesel market is explained. The second essay aims to evaluate the new incentive system for biodiesel in South Korea, which keeps the blend mandate but abolishes tax credits for government revenues. To estimate changed welfare from the new policy, a multivariate stochastic simulation method is applied into time-series data for the last five years. From the simulation results, the new biodiesel policy will lead government revenues to increases with the abolishment of tax credit. However, increased prices of blended diesel will cause to decrease demands of both biodiesel and blended diesel, so consumer and producer surplus in the transport fuel market will decrease. In the third essay, the Regression - Seasonal Autoregressive Integrated Moving Average (REGSARIMA) model is employed to predict the impact of air temperature on daily peak load demand in Houston. Compared with ARIMA and Seasonal Model, a REGARIMA model provides the more accurate prediction for daily peak load demand for the short term. The estimated results reveal air temperature in the Houston areas causes an increase in electricity consumption for cooling but to save that for heating. Since the daily peak electricity consumption is significantly affected by hot air temperature, this study makes a conclusion that it is necessary to establish policies to reduce urban heat island phenomena in Houston.

投資組合保險的概念發源自1980年代，對於較保守或是對於股市未來走勢不清楚的投資人來說，是一種不錯的投資策略，既可以保障原本所投資的本金，亦可參與上方的獲利。投資組合保險策略所運用的範疇很廣，尤其適用於大筆資金之持有者，且只願意承受一定範圍的損失風險，如：退撫基金、保險基金或各類信託基金之基金經理人。 本研究以台灣50ETF(指數股票型基金)為研究對象，探討複製性賣權及固定比例投資組合保險等兩種資產配置策略，在不同市況下(2006年至2011年)之績效，並與買入持有策略做比較。其中，本文以GARCH波動度模型估計複製性賣權策略中之波動度；在CPPI策略中，由於考量到不同市場狀況下，投資人之風險偏好程度應會有所不同，風險乘數亦會有所改變，因此本文將風險乘數最適化，以改善傳統之固定風險乘數CPPI策略。 由本研究之實證結果可以得到以下結論： 1. 複製性賣權策略在空頭市場之績效會比買入持有策略及台灣50ETF好。然而，在大空頭時，由於股價急速下滑，導致資產配置來不及調整，而產生保險誤差。另外，複製性賣權在多頭市況下，較低的保本比例，會帶來較高之報酬。 2. CPPI策略在各種市況下，其績效大致都會優於買入持有策略，且完全沒有出現保險誤差，但只有在空頭走勢下，CPPI會打敗市場，原因在於CPPI發揮了保護下檔風險的功能，且說明了投資組合保險策略之目的並非超越市場報酬。 3. 將複製性賣權策略與CPPI策略相比時，從報酬率來看，空頭市場下CPPI的保護功能較複製性賣權強，而多頭或盤整市況下，並無一致的結果。從Sharpe ratio、長期相對平均成本、上方獲取率損失等績效指標，CPPI大致上都比複製性賣權好得多。