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跳躍過程下利率期間結構之估計與預測歐陽德耀, Ou Yang De Yau Unknown Date (has links)
摘要
利率期間結構是指各種零息債券的殖利率與剩餘期間的對應關係,研究利率行為對資產管理及資產訂價都有非常重要的意義。在一般的資產訂價過程中,可以區分成兩股力量,一是”normal” diffusion,代表的是連續的新資訊導致資產的邊際改變。另一股力量則是”rare” jump,指的是少數的重要的資訊,是在間斷的時點釋放,造成一個超越邊際變動的影響。本論文探討的是,在政府貨幣政策所發出的跳動訊息下,對利率期間結構所產生的影響,並利用Duffie and Kan於1996年所提出的仿射利率期間結構(Affine term structure),加入跳躍過程下,利用一般化動差法(GMM, Generalized Method of Moments),估計模型的參數,進而預測未來利率的走勢。
在第一章中我們將說明整個利率期間結構理論的演進,從利率期間結構的三大理論:預期理論(the expectation hypothesis)、期間偏好理論(the preferred habitat theory)、市場區隔論(the segmented markets theory),到近二十年來發展的連續隨機利率模型。
而第二章主要在介紹加入跳躍過程的仿射利率期間結構(Affine term structure),並對政府貨幣政策的行為做一個模型設定,以便之後的參數估計。
在第三章我們可以知道詳細的一般化動差法(GMM, Generalized Method of Moments)估計方式,運用在本論文模型上的用法。第四章則真正利用由1994年(民83年)11月24日,至2001年2月1日,共1738筆央行重貼現率,及180天期CP2的日資料,來估計模型的參數。當模型參數得知後,代入求解出的零息債券方程式,來估計利率期間結構。
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監理寬容下保險安定基金公平費率 / Fair Insurance Guaranty Premium in the Presence of Regulatory Forbearance鄭力瑀, Cheng, Li Yu Unknown Date (has links)
受2008年金融海嘯影響,人壽保險業因資本及信用市場之系統性風險而導致帳列資產價值大幅減損,進一步影響壽險公司清償能力,而主管機關為兼顧審慎監理與市場穩定原則,而採行資本監理寬容措施,卻使得資本不足之保險公司缺口擴大。另外,保險安定基金以保費為基礎徵收單一費率,加劇保險公司間交叉補貼之情形。因此,如何透過以責任準備金為基礎,計算公平合理之風險差別費率,以避免產生影響其他保險公司正常經營之系統性風險,抑或引發保險公司道德風險,為本文研究之主要議題。
本文與過去文獻主要之差異為:(1) 資產模型依資產配置方式,使用蒙地卡羅模擬詳盡現金流路徑,著重於描述壽險業之情境;(2) 股票型風險性資產加入跳躍過程 (Jump) 與隨機波動兩種情境,以表達壽險業資產端承受資本市場變動加劇之風險;(3) 考慮政府監理寬容措施,以描述主管機關對於壽險業監理態度。
依蒙地卡羅模擬法試算保險安定基金公平費率,研究結果發現:(1)監理寬容期限增加時,安定基金公平費率增加;(2)監理標準提高,安定基金公平費率有先降後升之效果;(3)保險公司財務槓桿比例增加時,安定基金公平費率上升。 / Due to the global financial crisis in 2008 that resulted in systematic risks in the equity and credit market, it creates significant deprecation in the life insurers’ balance sheet which affect insurers’ solvency. In order to retain prudent supervision and market stability, the authority has announced capital temporal relief plan that may make insolvency insurer worse. Recent occurrences of financial distress to some insurers have raised questions about whether the current guaranty system that charge a flat levy rate in premium-based is adequate to protect policyholders. A risk-weighted levy rate in reserve-based has been proposed to establish reasonable contribution method which can avoid high risk insurers’ moral hazard and protect the other insurers from further systematic risks.
A brief summary of the advantages of this paper is listed below:(1) By Monte Carol simulation method, detailed cash flow of insurer’s asset allocation can be used to describe the risk preference of life insurer. (2) Our stock model incorporates jump diffusion and stochastic volatility in order to reflect that life insurers face increasing volatility in capital market. (3) Consider regulatory forbearance to represent government’s attitude to life insurers.
We calculate fair guaranty premium through Monte Carol simulation method. We find that: (1) Fair premium increases as extending the period of regulatory forbearance. (2) As regulatory criterion raises fair premium decreases at first, but increases if regulatory criterion reaches certain level. (3) Increasing leverage ratio of the insurer results in increasing fair premium.
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考量信用風險下之海外可轉債評價 / Pricing Euro-Convertible Bonds with Credit Risk吳岱恩, Wu, Tai En Unknown Date (has links)
鑒於近年全球海外可轉換公司債發行檔數大增,然而以此商品為研究主題的文獻並不多,於是決定以此為研究目標。
影響海外可轉換公司債的價格因素包括股票價格、匯率、國內利率、國外利率和發行公司的違約機率,因此可買回、可賣回海外可轉換公司債是一個複雜的商品,而評價也較為困難。本文採用三維度二項樹和最小平方蒙地卡羅法建立評價海外可轉債的數值模型。為了更貼近真實世界,本文考量各變數間相關性和動態信用風險;另外,為了使評價更為精準,於股價過程中加入跳躍過程。
本文將模型運用至兩檔台灣公司所發行的海外可轉債,發現理論價格傾向於高估,但是理論價格與市價極為接近,尤其當以最小平方蒙地卡羅法評價時。另外本文也針對發行條件和模型中各個變數作敏感度分析,其中重要的是發現股票波動度、股票與匯率間相關係數在海外可轉債評價中扮演重要的角色。 / The number of Euro-convertible bonds issued has highly increased in the early 2010s. However, the related literature is barely found. This paper studies the pricing models of this investment product. Euro-convertible bonds are complex instruments affected by the credit risk of the issuers, the dynamic process of stock prices, the term structure of the interest rate and the movement of the exchange rate in the same time. Accordingly, building the ECB pricing model is a hard work.
This paper presents a model considering the dynamic credit risk and jump in stock price process to make valuation more precise. Another advantage of models in this paper is use of stochastic interest rates for both local and foreign so as to make the model more staying with the real world. The other advantage is taking the correlation between each random variables into account. For pricing the Euro-convertible bonds, the numerical methodologies used in this paper are three-dimension binomial tree and least squares Monte Carlo approach.
For purpose of assessing the performance of the model, two Euro-convertible bonds issued by Taiwan companies are chosen as samples and the difference between the theoretical price and market price during its issue period are provided. The results demonstrate that in spite of pretty slight overestimation, the least squares Monte Carlo simulation does a better job.
In addition, this paper performs several kinds of sensitivity analysis to have in-depth understanding about the models. The consequence shows that the volatility of a stock return and the correlation between stock and exchange rate play a central role in ECB valuations.
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確定提撥制退休金之評價:馬可夫調控跳躍過程模型下股價指數之實證 / Valuation of a defined contribution pension plan: evidence from stock indices under Markov-Modulated jump diffusion model張玉華, Chang, Yu Hua Unknown Date (has links)
退休金是退休人未來生活的依靠,確保在退休後能得到適足的退休給付,政府在退休金上實施保證收益制度,此制度為最低保證利率與投資報酬率連結。本文探討退休金給付標準為確定提撥制,當退休金的投資報酬率是根據其連結之股價指數的表現來計算時,股價指數報酬率的模型假設為馬可夫調控跳躍過程模型,考慮市場狀態與布朗運動項、跳躍項的跳躍頻率相關,即為Elliot et al. (2007) 的模型特例。使用1999年至2012年的道瓊工業指數與S&P 500指數的股價指數對數報酬率作為研究資料,採用EM演算法估計參數及SEM演算法估計參數共變異數矩陣。透過概似比檢定說明馬可夫調控跳躍過程模型比狀態轉換模型、跳躍風險下狀態轉換模型更適合描述股價指數報酬率變動情形,也驗證馬可夫調控跳躍過程模型具有描述報酬率不對稱、高狹峰及波動叢聚的特性。最後,假設最低保證利率為固定下,利用Esscher轉換法計算不同模型下型I保證之確定提撥制退休金的評價公式,從公式中可看出受雇人提領的退休金價值可分為政府補助與個人帳戶擁有之退休金兩部分。以執行敏感度分析探討估計參數對於馬可夫調控跳躍過程模型評價公式的影響,而型II保證之確定提撥制退休金的價值則以蒙地卡羅法模擬並探討其敏感度分析結果。 / Pension plan make people a guarantee life in their retirement. In order to ensure the appropriate amount of pension plan, government guarantees associated with pension plan which ties minimum rate of return guarantees and underlying asset rate of return. In this paper, we discussed the pension plan with defined contribution (DC). When the return of asset is based on the stock indices, the return model was set on the assumption that markov-modulated jump diffusion model (MMJDM) could the Brownian motion term and jump rate be both related to market states. This model is the specific case of Elliot et al. (2007) offering. The sample observations is Dow-Jones industrial average and S&P 500 index from 1999 to 2012 by logarithm return of the stock indices. We estimated the parameters by the Expectation-Maximization (EM) algorithm and calculated the covariance matrix of the estimates by supplemented EM (SEM) algorithm. Through the likelihood ratio test (LRT), the data fitted the MMJDM better than other models. The empirical evidence indicated that the MMJDM could describe the asset return for asymmetric, leptokurtic, volatility clustering particularly. Finally, we derived different model's valuation formula for DC pension plan with type-I guarantee by Esscher transformation under rate of return guarantees is constant. From the formula, the value of the pension plan could divide into two segment: government supplement and employees deposit made pension to their personal bank account. And then, we done sensitivity analysis through the MMJDM valuation formula. We used Monte Carlo simulations to evaluate the valuation of DC pension plan with type-II guarantee and discussed it from sensitivity analysis.
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