[pt] Algumas literaturas sugerem que a volatilidade implícita das opções de compra de ações não deve ser utilizada como estimador para a volatilidade futura. Contudo, estudos recentes e aplicados ao mercado brasileiro de ações comprovaram que em determinados casos existe relação entre a volatilidade implícita e a volatilidade real (ou realizada). Isso significa dizer que a primeira traz informações sobre a última. Nesse contexto, o objetivo deste estudo é comparar a volatilidade implícita de dois modelos de apreçamento de opções com a volatilidade realizada. Entre os modelos de Black-Scholes (1973) e Corrado-Su (1996), utilizando dados de opções de Petrobras e Vale do Rio Doce, foram calculados, através do erro quadrático, aqueles resultados que mais se aproximaram da volatilidade realizada. Estes resultados trazem indícios de que o modelo de Black-Scholes, em média, foi superior ao Corrado-Su no período que vai de janeiro de 2005 a julho de 2009. Porém, o último, por levar em consideração a assimetria e a curtose da distribuição de retornos, chegou mais perto da volatilidade realizada apenas em alguns momentos específicos das economias brasileira e mundial. / [en] Several authors have proposed that implied volatility from purchase options should not be used as an estimate for future volatility. However, recent studies applied to the Brazilian stock market proved that in certain cases there is relation between implied volatility and realized volatility. This means that the first one provides information on the last. In this context, the objective of this study is to compare implied volatilities from two different option pricing models against the realized volatility. The models are Black-Scholes (1973) and Corrado-Su (1996). Working with purchase options on Petrobras and Vale do Rio Doce, it was calculated the difference, by quadratic error, between the implied volatility of these models and the realized volatility. After this, it was checked those results that came closer to the realized volatility. The results provide evidence that the Black-Scholes model, on average, has higher performance than Corrado-Su from January 2005 to July 2009. However, Corrado-Su by taking into account the asymmetry and kurtosis of the distribution of returns came closer to the realized volatility only in specific moments of the Brazilian and global economies.

Este trabalho tem por objetivo verificar a eficácia do modelo parametrizado SVI (Stochastic Volatility Inspired), apresentando-o como um método alternativo à construção da volatilidade implícita para opções de ações e de índice no mercado brasileiro. Primeiramente, o conceito financeiro de opção e sua teoria de precificação são apresentados, incluindo os modelos de Black-Scholes e Heston, a importância da volatilidade implícita e seu comportamento estocástico e detalhando o funcionamento de cada parâmetro do modelo SVI (Stochastic Volatility Inspired). Um algoritmo é desenvolvido em cima da base teórica, assim como sua implementação computacional. Além disso, são feitos experimentos com dados de mercado reais e seus resultados analisados e comparados com os de publicações anteriores. / This work aims to verify the efficiency of parameterized SVI (Stochastic Volatility Inspired) model, presenting it as an alternative method to construct the implied volatility for stock and index options in Brazilian market. First, the financial option concept and its pricing theory are presented, including Black-Scholes and Heston models, the importance of implied volatility and its stochastic behavior and detailing the operation of each parameter of the SVI (Stochastic Volatility Inspired) model. An algorithm is developed on top of the theoretical basis, as well as its computational implementation. In addition, experiments are performed with real market data and their results are analyzed and compared with those of previous publications.

Como a volatilidade é a única variável não observada nas fórmulas padrão de apreçamento de opções, o mercado financeiro utiliza amplamente o conceito de volatilidade implícita, isto é, a volatilidade que ao ser aplicada na fórmula de apreçamento resulte no preço correto (observado) das opções negociadas. Por isso, entender como as volatilidades implícitas das diversas opções de dólar negociadas na BM&F, o objeto de nosso estudo, variam ao longo do tempo e como estas se relacionam é importante para a análise de risco de carteiras de opções de dólar/real bem como para o apreçamento de derivativos cambiais exóticos ou pouco líquidos. A proposta de nosso estudo é, portanto, verificar se as observações da literatura técnica em diversos mercados também são válidas para as opções de dólar negociadas na BM&F: que as volatilidades implícitas não são constantes e que há uma relação entre as variações das volatilidades implícitas e as variações do valor do ativo objeto. Para alcançar este objetivo, aplicaremos a análise de componentes principais em nosso estudo. Com esta metodologia, reduziremos as variáveis aleatórias que representam o processo das volatilidades implícitas em um número menor de variáveis ortogonais, facilitando a análise dos dados obtidos. / Volatility is the only unobserved variable in the standard option pricing formulas and hence implied volatility is a concept widely adopted by the financial market, meaning the volatility which would make the formula yield the options real market price. Therefore, understanding how the implied volatility of the options on dollar traded at BM&F, the subject of our study, vary over time is important for risk analysis over dollar option books and for pricing of exotic or illiquid derivatives Our works proposal is to verify if the observations made by the technical literature over several markets could also be applied to the options on dollar traded at BM&F: implied volatilities do vary over time and there is a relation between this variation and the variation of the underlying asset price. In order to fulfill these goals, we will apply principal component analysis in our study. This methodology will help us analyze the data by reducing the number of variables that represent the implied volatility process into a few orthogonal variables.

Many past literatures have examined the predictive power of implied volatility versus that of historical volatility, but they have showed divergent conclusions. One of the major differences among these studies is the methods that they used to obtain implied volatility. The VIX index, introduced in 1993, provides a model-free and directly observable source of implied volatility data. The VIX futures is an actively traded VIX derivative product, and its prices are believed to contain market’s expectation about future volatility. By analyzing the relationship between the VIX futures prices and the realized volatilities of the 30-day period that these VIX futures contracts cover, this paper finds that the VIX futures contracts with shorter maturities have predictive power on future realized volatility, but they are upwardly biased estimates. The predictive power, however, decreases as the time to maturity increases. The outstanding VIX futures contracts with the nearest expiration dates outperform GARCH estimates based on historical return data at predicting future realized volatility.

To understand and model the dynamics of the implied volatility smile is essential for trading, pricing and risk management portfolio. We suggest a  linear Kalman filter for updating of the Stochastic Volatility Inspired (SVI) model of the volatility. From a risk management perspective we generate the 1-day ahead forecast of profit and loss (P\&L) of option portfolios. We compare the estimation of the implied volatility using the SVI model with the cubic polynomial model. We find that the SVI Kalman filter has outperformed the  others.

This study develops a multi-period log-return quantile forecasting procedure to evaluate the performance of eleven nearby commodity futures contracts (NCFC) using a sample of 897 daily price observations and at-the-money (ATM) put and call implied volatilities of the corresponding prices for the period from 1/16/2008 to 7/29/2011. The statistical approach employs dynamic log-returns quantile regression models to forecast price densities using implied volatilities (IVs) and factors estimated through principal component analysis (PCA) from the IVs, pooled IVs and lagged returns. Extensive in-sample and out-of-sample analyses are conducted, including assessment of excess trading returns, and evaluations of several combinations of quantiles, model specifications, and NCFC's. The results suggest that the IV-PCA-factors, particularly pooled return-IV-PCA-factors, improve quantile forecasting power relative to models using only individual IV information. The ratio of the put-IV to the call-IV is also found to improve quantile forecasting performance of log returns. Improvements in quantile forecasting performance are found to be better in the tails of the distribution than in the center. Trading performance based on quantile forecasts from the models above generated significant excess returns. Finally, the fact that the single IV forecasts were outperformed by their quantile regression (QR) counterparts suggests that the conditional distribution of the log-returns is not normal.

Due to the sharpen regulation of the Swedish plain vanilla warrant in 2006 and the recent increase in trade among private investors, this thesis examined the informa-tion efficiency of Swedish plain vanilla warrants. This was done in three different ways. First the theoretical Black & Scholes (B&S) price was tested against the ac-tual market price. Secondly likelihood ratio test statistics was used to see whether information regarding past returns added any information to that already captured by the implied volatility (IV) generated from observed warrant market prices via the B&S model. The third method used was a comparison of the IV´s among com-parable warrants. As the regulation of the Swedish plain vanilla warrant market states that only certified issuer are allowed short calls and puts, the self adjusting price mechanism found in the option market doesn’t exist on this market. As a con-sequence of this, investors on this market is reliant of accurate ask and bid prices from the issuers. Further, the information efficiency of a capital market is of es-sence for capital allocation, price discovery and risk management. The results from all three tests rejected the information efficiency hypothesis of the sample. Thus concluding that the included warrants in this thesis are none ideally for activities such as capital allocation, price discovery and risk management.

This article examines the hedging positions derived from the Black-Scholes(B-S) model and the GARCH(1,1) models, respectively, when the log returns of underlying asset exhibits GARCH(1,1) process. The result shows that Black-Scholes and GARCH options deltas, one of the hedging parameters, are similar for near-the-money options, and Black-Scholes options delta is higher then GARCH delta in absolute terms when the options are deep out-of-money, and Black-Scholes options delta is lower then GARCH delta in absolute terms when the options are deep in-the-money. Simulation study of hedging procedure of GARCH(1,1) and B-S models are performed, which also support the above findings.

依據中華民國證券櫃檯買賣中心公佈之新金融商品業務概況，我們可以看出債券選擇權雖然到2004年7月才核准開放，但是從年度成交金額，債券選擇權均居所有債券與利率衍生性商品之冠。由於債券選擇權市場仍處於開放初期，相關資料如債券選擇權隱含波動率取得不易，因此關於台灣債券選擇權市場並未如指數選擇權市場吸引很多學術與實務界之注目。 本研究嘗試對於台灣債券選擇權市場，從評價模型、市場實務概況描述及未來可能之發展，作進一步之研究；此外，本文亦參酌Goodman and Ho（1997）所進行之美國債券選擇權損益之實證研究，來探討賣出債券「買進選擇權」之一方，是否能同樣在台灣債券選擇權市場獲得相對等之報酬。 本實證分析方法基本上是假設，「債券買權」賣方賣出履約殖利率為一個基本點價外之「債券買權」，選擇權存續期間是以兩個星期為一個循環，以中華民國證券櫃檯買賣中心公佈之每日10年期指標公債加權平均殖利率作為相對應部位調整之依據，分別代入實際波動率與期初「債券買權」之隱含波動率，進行Delta Neutral避險，且假設債券拆借與資金融通利率為中華民國證券櫃檯買賣中心公佈之等殖成交行情表（附條件）中所揭露之附條件利率，來探討賣方是否能夠賺取一定合理之報酬率及其可能面對之風險。 從2005年4月至2005年11月底之實證期間，共計13個循環週期，我們發現下列幾個現象： ◆債券買權與賣權之隱含波動率普遍高於實際波動率，賣權隱含波動率又高於買權。 ◆以賣出債券買權為例，在不考慮交易成本下，賣出買權之一方均能獲利，但損益之變異性都相當大。 ◆在避險波動率參數之使用上，代入實際波動率，不論是從損益之絕對數值或每單位風險報酬，均優於代入期初買權隱含波動率。 ◆從等殖成交行情表（附條件）中所揭露之附條件利率，即債券融資與融券利率，其波動性遠大於債券殖利率，因此在進行債券選擇權交易時必需將此列入評價之重要考量因素。 ◆如果考慮權利金收入，由於目前稅法無法與避險損失互抵，必需被課徵25%營利事業所得稅，因此選擇權賣方均無法獲利。 / According to the fact reports of OTC derivatives released by GraTai Securities Market (GTSM) in 2005, trading value of bond option was top of all interest rate derivatives and bond derivatives, though it was opened lately in July 2004. Due to the difficulty to get the market information like implied volatility of options, we haven’t seen considerable studies on Taiwan bond option market. Owing to the writer of this paper serves in this field, we can take advantage of collecting these data from Interdealer brokers and dealers. Accordingly, we have ground to develop this research. In this paper, we begin our discussion by presenting the landscape of Taiwan bond option market and then turn to review the basic models. Lastly, we reference the empirical study of US OTC Treasury option done by Goodman and Ho (1997) to construct the framework for measuring how investors are fairly compensated by selling call in Taiwan bond option market. To evaluate the profit and risk of option writing, we assume writer can sell two-week call options on ten-year Treasury note at market implied volatility, with a strike yield at one basis point out of daily closing yield. Option writer uses daily closing yields to do the delta neutral hedge. Besides, we take overnight call loan rates of Electronic Bond Trading System in GTSM as the borrowing and lending rates of government bond. Over the empirical period of 2005.04.1-2005.11.30, several circumstances can be found from this study. 1.In average, the implied volatilities are higher than actual volatility. This is in agreement with the results of Goodman and Ho (1997). Besides, implied volatility of put option is generally higher than call option. 2.Without considering transaction cost, call option writer can have vulnerable profit from selling volatility. 3.Adoption of actual volatility can bring better absolute profit and risk-adjusted return than implied volatility in the option valuation. 4.In this article, it shows a striking effect of the borrowing and lending rates of government bonds on the movement of implied volatility spread between call and put. 5.Under current Act of Income Tax, the hedging loss of option writer cannot be offset by premium income. Therefore, call writer can not make profit after tax.

這一篇文章主要的目的在於檢視 Bollen and Whaley (2004) 所提出來的淨買壓假說 (Net Buying Pressure Hypothesis) 在台指選擇權市場上是否一樣有相同的現象。 在本文的研究當中，我們也發現台指選擇權市場，較符合套利限制假說，包括落後一期的隱含波動率的變化和當期的隱含波動率的變化呈現負相關的現象以及價平選擇權的淨買壓對於價外的選擇權隱含波動率影響的程度較價外選擇權的淨買壓來的小。但是從淨買壓來看，其結果和S&P 500指數選擇權不同，因為台指選擇權的淨買壓，除了深度價外賣權以外，全部都是負數。 另外，本研究也將樣本資料區間中，另外分成總統大選前以及總統大選後這兩個階段來分析選擇權的淨買壓是否對於選擇權的隱含波動率變化仍然具有影響力，其結果發現在總統大選前，對買權來說，買權的市場行為符合套利限制假說。另外對賣權而言，在總統大選前，賣權的市場行為符合學習假說。在總統大選後，對買權而言，買權的市場行為改變為符合學習假說。而對賣權而言，在總統大選後，賣權的市場行為並沒有改變，仍然符合學習假說。 / This paper mainly examines that whether the Net Buying Pressure Hypothesis which is issued by Bollen and Whaley (2004) fits the options market in Taiwan? In this paper, we find that the options market in Taiwan supports the limits to arbitrage hypothesis. These phenomena include the changes of implied volatility with lag one is negative with the changes of implied volatility and the net buying pressure of the at-the-money options have less effect on the changes of the implied volatility in comparison with that of out-of-the-money options. But form the prospect of the net buying pressure, the result is different from that of the S&P 500 index options. This is because the net buying pressures in the options markets in Taiwan are all negative besides the deep-out-of-the-money put options. Besides, this paper also analyzes that whether the net buying pressure in the options market will affect the changes of implied volatility of the options before the President election and after the President election. Our research finds that before the election, the market behaviors support the limits to arbitrate hypothesis for call options. But the market behaviors support the learning hypothesis for put options. After the election, the market behaviors support the learning hypothesis for call options. For put options, the results are the same, which support the learning hypothesis.