Option smiling when investors’ estimates of asset volatility disagree

This study sheds light on why heterogeneous beliefs in volatility manifest the smile effect of options and how the degree of belief disagreement influences option-implied volatility. It is found that when investors’ level of heterogeneous beliefs increases, agents who over estimate volatility raise their subjective probability about those outer dividend states and hence increase more consumption to those states. As a result, an increase of consumption causes a decrease of their marginal rate of transformation in outer states. The raising subjective probability increases the prices of outer states, while the lower marginal rate of transformation decreases the prices of that. However, the influence of the former dominates the latter, causing a fatter tail of the state-price density. As a consequence, the values increase for those call options with high strike prices and put options with low strike prices, leading to a U-shaped implied volatility and hence causes a smell effect.     

Time-varying relationship of news sentiment,implied volatility and stock returns

I examine the relationship between aggregate news sentiment, S&P 500 index (SPX) returns, and changes in the implied volatility index (VIX). I find a significant negative contemporaneous relationship between changes in VIX and both news sentiment and stock returns. This relationship is asymmetric whereby changes in VIX are larger following negative news and/or stock market declines. Vector autoregression (VAR) analysis of the dynamics and cross-dependencies between variables reveals a strong positive relationship between previous and current period changes in implied volatility and stock returns, while current period and lagged news sentiment has a significant positive (negative) relationship with stock returns (changes in VIX). I develop a simple trading strategy whereby high (low) levels of implied volatility signal attractive opportunities to take short (long) positions in the underlying index, while extremely negative (positive) news sentiment signals opportunities to enter short (long) index positions. The investor fear gauge (VIX) appears to perform better than news sentiment measures in forecasting future returns.     

The relation between asset growth and the cross-section of stock returns: Evidence from the Chinese stock market

This study examines the effect of firm investment on stock returns by using data on the Chinese stock market. We find that stocks with higher investment experience lower future returns and there is an obvious investment effect in the Chinese stock market. The investment effect is stronger for firms that have higher cash flows, lower debt or for state-owned firms. We further explore the relation between investment and returns over the 3 years around portfolio formation. The results show that the high investment firms earn higher returns than low investment firms before portfolio formation; however the high investment firms earn lower returns than low investment firms after portfolio formation, such evidence is supportive of investor's overreaction explanation. Additionally, the stock returns don't necessarily decrease after investment, and the stock returns don't significantly positively correlate with firm profitability or book-to-market, so the result don't support risk-based explanation. Overall, both our portfolio sort and two-stage cross-sectional regression analysis show that behavioral finance theories are better than risk-based theories in explaining the investment anomaly. Evidence from the Chinese stock market provides a useful perspective to understand the debate on the investment anomaly.     

New estimates of time-varying currency betas: A trivariate BEKK approach

This paper examines the conditional time-varying currency betas from five developed markets and four emerging markets. We employ a modified trivariate BEKK-GARCH-in-mean model of Engle and Kroner (1995) to estimate the time-varying conditional variance and covariance of returns of stock index, the world market portfolio and changes in bilateral exchange rate between the US dollar and the local currency. It is found that currency betas are more volatile than those of the world market betas. Currency betas in emerging markets are more volatile than those in the developed markets. Moreover, we find evidence of long-memory in currency betas. The usefulness of time-varying currency betas are illustrated by two applications.     

Liquidity and equity returns in Borsa Istanbul

We investigate the relationship between expected returns and liquidity measures in Borsa Istanbul. To do so, we gather a wide range of illiquidity measures that can be applied to the market. Firm-level cross-sectional regressions indicate that there is a positive relationship between various illiquidity measures and one- to six-month ahead stock returns. Findings of the article are robust after using different sample periods and controlling for well-known priced factors, such as market beta, size, book-to-market ratio and momentum. The portfolio analysis reveals that stocks that are in the highest illiquidity quintile earn 7.2%–19.2% higher risk-adjusted annual returns than those in the lowest illiquidity quintile. The illiquidity premium is stronger for small stocks and stocks with higher return volatility and it increases (decreases) during periods of extremely low (high) market returns.     

Resuscitating businessman risk: A rationale for familiarity-based portfolios

This paper studies two frequently observed portfolio behaviors that are seemingly inconsistent with rational portfolio choice. The first is the tendency of workers and entrepreneurs to hold their companyʼs stock. The second is the propensity of workers to limit their equity holdings through time. The explanation offered here for both of these behaviors lies in the option to switch jobs when oneʼs company does poorly. This is equivalent to holding put options on oneʼs own company stock and call options on the other companyʼs stock, where both options must be exercised at the same time. Given these initial undiversified implicit financial holdings, workers need to allocate a relatively large share of their regular financial assets to their own companyʼs stock and a relatively small share to the stock of their alternative employment simply to restore overall portfolio balance. Although this effect can only create some hedging demand for companyʼs stock, it is a factor of potentially major import for assessing the suitability of workersʼ financial decisions. I find that, under certain conditions, workers optimally hold almost 40% of their financial wealth in their companyʼs stock.     

含权债券定价的统一框架及其数值分析

本文从理论上推导了一般债券定价的偏微分方程，详细分析了包含欧式和美式看涨和看跌期权的4类债券，并给出了4类含权债券定价的边界条件。利用隐性差分法数值求解了偏微分方程，针对4类期权对不同利率参数的敏感性进行了分析。     

Global idiosyncratic risk moments

We investigate a global cross-sectional relation between idiosyncratic risk moments and expected stock returns by suggesting three global idiosyncratic volatility, skewness, and kurtosis risk factors. We also suggest two global small minus big and high minus low risk proxies for estimating return residuals of the test assets from a global asset pricing model. To perform robustness checks, we suggest other four global risk factors of momentum, leverage, bid-ask spread, and liquidity. We find a significant negative relation between stock portfolio returns and the global moments, and the cross section of stock returns reflects a significant negative price of risk for global idiosyncratic skewness (?0.13%) and idiosyncratic volatility (?1.85%) and a positive and significant price of risk for global idiosyncratic kurtosis. We find that our suggested risk factors are key drivers of risk premia in stock market and are robust to various checks. These factors also can forecast the gross domestic product growth over the sample period.     

Rolling settlement and market liquidity

This paper investigates the impact on UK stock and option markets of the change from an account based settlement system to a rolling settlement procedure. Such a change increases the transaction costs of short-term margin traders, and is likely to impact on the liquidity of the underlying market, as well as trading in the options market. Evidence is presented that the settlement procedure does impact on the liquidity of the market. Further, we find that rolling settlement increased market liquidity, consistent with the exit of margin traders as a result of the increase in short selling costs. Associated with this increase in liquidity is a significant reduction in nonoptionable stock trading volume, implying that margin trading may have been more prevalent in stocks without options. Finally, it is shown that while trading in stock options increased, the volatilities implied from call and put option prices indicate that put options have become relatively more expensive. This reflects the change in demand induced by the new settlement procedure, especially in terms of the increase in short selling costs.     

A risk index to model uncertain portfolio investment with options

This paper models the portfolio investment performance with options by using a risk index, which is defined as the average loss below the risk-free interest rate. Using a risk-free interest rate as the uniform reference rate for all portfolios, the risk index offers an easier-to-compare loss value than the value-at-risk return, where portfolio specific references are used to calculate the average losses. Besides, uncertainty theory is used in the paper to derive the portfolio decision when stock prices are subject to experts' estimations. By analytical computation and empirical analysis, we find that portfolios considering options generate better return than the ones without options. The empirical analysis reveals that the options can effectively hedge the risk, and the call option with a higher exercise price offers higher return per unit of option premium. Furthermore, our proposed model produces higher expected return in most cases than the model where the risk is measured by the chance of the total return failing to reach the threshold level of return.     

The tax (dis)advantage of a firm issuing options on its own stock

It is common for firms to issue or purchase options on the firm's own stock. Examples include convertible bonds, warrants, call options as employee compensation, and the sale of put options as part of share repurchase programs. This paper shows that option positions with implicit borrowing—such as put sales and call purchases—are tax-disadvantaged relative to the equivalent synthetic option with explicit borrowing. Conversely, option positions with implicit lending—such as warrants—are tax-advantaged. I also show that firms are better off from a tax perspective issuing bifurcated convertible bonds—bonds plus warrants—rather than an otherwise equivalent standard convertible.     

A Re-examination of the Performance of Value Strategies in the Athens Stock Exchange

This study tests the performance of contrarian (value) strategies in the Athens Stock Exchange (ASE) in a recent period of time (2003–8) on the basis of the price to earnings ratios, dividend yields, firm size (market value), market to book ratios, financial leverage ratios, and market beta. Apart from the univariate portfolio analysis, we implement a novel panel data analysis based on the procedure suggested by Pesaran (2004, Econometrica 74:967–1012, 2006) that provides a valid estimation and inference under cross sectional dependence. Our portfolio analysis results highlight for investors in the ASE the superiority of value strategies formed on the basis of stocks with low price-to-earnings, high dividend yield ratios, and low market-to-book ratios. Our panel data analysis results depend on whether or not we correct for the problem of cross-sectional correlation in the regression residuals as suggested by Pesaran’s (Econometrica 74:967–1012, 2006) method. When we correct for this problem, we obtain evidence which support only a negative association between annual stock returns and market-to-book ratios. This may imply to investors that an adoption of a value strategy based on the market-to-book ratio may constitute a safer option compared with the other two alternatives suggested by the portfolio analysis results.     

The relation between the informational content of implied volatility and arbitrage costs: Evidence from the Oslo Stock Exchange

This study investigates the proposition that volatility of stock returns can be predicted from the volatility implied by options on the Oslo Stock Exchange (OSE), conditional on the ability to perform arbitrage. Insights into the relation between the informational content of implied volatility and arbitrage cost can be distilled from Oslo Stock Exchange data. For Norwegian firms, options and their underlying stock trade on the Oslo Stock Exchange and have an overlapping set of market makers thereby lowering the cost of arbitrage. Other components of arbitrage trading costs, liquidity and dispersion of stock return volatility, vary widely across Norwegian firms. Moreover, restriction on the short selling of stock in Oslo allows further insight into the role of arbitrage costs in determining the informational content of implied volatility. The results yield support for the arbitrage cost hypothesis: the lower the arbitrage cost between the stock and the option, the greater the informational content of implied volatility.     

Do Survey Probabilities Match Financial Market Beliefs?

This article considers whether survey respondents' views regarding the likelihood of stock index returns exceeding specific thresholds are comparable to market views indicated by index options with strikes at analogous thresholds. It is motivated by the observation that the wording used to elicit subjective beliefs in surveys about expected future returns resembles the question a purchaser of a call option might ask. Building on this association, the authors document a similarity between the views of survey respondents and those of financial market participants as measured through call options, although the association is not 1-for-1. They find a closer association for those demonstrating a better understanding of the laws of probability, suggesting that numeracy affects the accuracy of an elicited response.     

Broad-based employee stock options grants and IPO firms

This paper examines the broad-based grant of employee stock options (ESOs) in the period following the Initial Public Offering (IPO). Stock option grants are used to reduce the negative effects of conflicts of interests associated with a firm's going public. The study documents that option grants can be seen as corporate governance instruments for a number of model specifications. Also, it is found that there is a robust relation between option grants and market and accounting returns, respectively. To the best of the authors' knowledge, no previous study has investigated the determinants of the grants of employee stock options in the post-IPO period to both upper-level and lower-level executives during a period of sixteen years. Because the cross-sectional data of this study amply encompasses more than a business cycle it is possible to examine the grants of ESOs across tight and soft labour markets. During the former type of labour market it appears that more options are granted. Also, the empirical results provide evidence that option grants are an increasing function of the employees’ benefits for the firm. Finally, the findings show that cash constrained firms appear to use employee stock option grants in place of cash compensation.     

Time-varying beta: a boundedly rational equilibrium approach

The conditional CAPM with time-varying betas has been widely used to explain the cross-section of asset returns. However, most of the literature on time-varying beta is motivated by econometric estimation using various latent risk factors rather than explicit modelling of the stochastic behaviour of betas through agents’ behaviour, such as momentum trading. Misspecification of beta risk and the lack of any theoretical guidance on how to specify risk factors based on the representative agent economy appear empirically challenging. In this paper, we set up a dynamic equilibrium model of a financial market with boundedly rational and heterogeneous agents within the mean-variance framework of repeated one-period optimisation and develop an explicit dynamic behaviour CAPM relation between the expected equilibrium returns and time-varying betas. By incorporating the two most commonly used types of investors, fundamentalists and chartists, into the model, we show that there is a systematic change in the market portfolio, risk-return relationships, and time varying betas when investors change their behaviour, such as the chartists acting as momentum traders. In particular, we demonstrate the stochastic nature of time-varying betas. We also show that the commonly used rolling window estimates of time-varying betas may not be consistent with the ex-ante betas implied by the equilibrium model. The results provide a number of insights into an understanding of time-varying beta.     

The determinants of exchange settlement practices and the implication of volatility smile: Evidence from the Taiwan Futures Exchange

This paper proposes that the Taiwan Futures Exchange (TAIFEX) adopts a linear extrapolation method to set the settlement price for the Taiwan Stock Exchange Capitalization Weighted Stock Index (TAIEX) options with less liquidity and thin trading. The empirical results indicate that the settlement-price-determined implied volatility is a smile function, consistent with the pattern of the market-price-determined implied volatility. Moreover, we examine the influence of economic factors on the TAIFEX's decision regarding the parameters of implied volatility function. Compared with the economic determinants of market-force-driven volatility parameters, the TAIFEX inappropriately values the impacts of the parameters of prior days, current stock returns, distribution of stock returns, long-term measurement of the stock market trend, market transaction cost, and time to maturity.     

Exploiting volatility movements in the Sydney futures exchange's bank bill contract

An appropriate stochastic model was fitted to one year of data on the implied volatility of options on 90 day bank accepted bill futures contracts traded in the Sydney Futures Exchange. The model used was ARIMA augmented with day of the week variables, an option time to maturity variable, and recent values of historic volatility. The high ex-post predictive accuracy of the model was then employed as the central element of a strategy of buy low/sell high volatility.We employed two trading schemes with suitably constructed Delta neutral portfolios comprising bill futures and call and put options on those futures over a period of six months, to test whether speculative trading profit could be earned. The existence of trading profits before transaction costs validated the potential of the buy low/sell high volatility strategies to generate speculative profits. The absence of any such trading profits after transaction costs however, showed that the market pricing of these securities is such that the dependencies within implied volatility cannot be profitably exploited.This result may be interpreted as evidence supporting an hypothesis of a semi-strong form of market efficiency.     

Do Aussie markets smile? Implied volatility functions and determinants

If options are correctly priced, the interpretation of volatility in the Black–Scholes model (as identifying the volatility of the underlying asset) is violated. The empirical relation between the model ‘implied volatility’ and the degree to which the option is in-the-money (moneyness) has been reported as resembling a U-shape (or ‘smile’) for options on currencies (and more of a ‘smirk’ for options on equities). In this article, using multivariate time-series analysis and employing an impulse response function, we investigate the structural relationships and dynamics of the volatility smile in relation to the option liquidity, key features of the underlying asset and market momentum. Our findings confirm evidence of a number of biases in the Black–Scholes model consistent with Chou et al. (2011) in regard to liquidity in both the underlying and the option itself, and with Peña et al. (1999) as to the importance of the option time to maturity. As well as delineating such biases as they co-relate both with each other and with the underlying asset volatility and momentum, we find that the pronounced smile is related to the differential sensitivities of in-the-money and out-of-the-money options, which itself suggests an explanation for the characteristic smile shape.     

THE SYSTEMATIC RISK OF DEBT: AUSTRALIAN EVIDENCE*

This paper examines systematic risk (betas) of Australian government debt securities for the period 1979–2004 and makes three contributions to academic research and practical debate. First, the empirical work provides direct evidence on the systematic risk of government debt, and provides a benchmark for estimating the systematic risk of corporate debt which is relevant for cost of capital estimation and for optimal portfolio selection by asset managers such as superannuation funds. Second, analysis of reasons for non‐zero (and time varying) betas for fixed income securities aids understanding of the primary sources of systematic risk. Third, the results cast light on the appropriate choice of maturity of risk free interest rate for use in the Capital Asset Pricing Model and have implications for the current applicability of historical estimates of the market risk premium. Debt betas are found to be, on average, significantly positive and (as expected) closely related, cross sectionally, to duration. They are, however, subject to significant time series variation, and over the past few years the pre‐existing positive correlation between bond and stock returns appears to have vanished.