black scholes approximations of call option prices with stochastic volatilities a note a piecewise linear weighting function for black scholes implied volatilities is used in conjunction with the black scholes call pricing model to approximate stochastic volatility european call prices a sensitivity analysis is conducted to compare simulated stochastic volatility call prices to the black scholes prices calculated with the weighted implied vo latilities the analysis indicates that a simple model can provide close approximations to the simulated prices with far less computational effort i introduction the volatility of the underlying asset is one of the more difficult parameters to estimate in any option pricing model the stochastic nature of the volatility of most financial assets is responsible for much of the difficulty while the early tests of the black scholes 1973 option pricing model rely upon historical prices for volatility estimates latane and rendleman s 1976 implied volatility technique has become the standard method of estimation unfortunately as beckers 1981 stresses although implied volatilities calculated from a stationary vari ance model may be of practical use it is inconsistent to use the black scholes model with a constant variance to obtain estimates of nonstationary variances l recent work conducted by hull and white 1987 and johnson and shanno 1987 has been directed at solving the problem of pricing european calls on assets with stochastic volatilities while hull and white provide a series solution for the case in which the variance and stock price are uncorrelated convergence is slow unless the variance of the assets volatility is relatively small for more general cases both hull and white and johnson and shanno rely upon monte carlo simulations to estimate option prices although the application of simulation techniques to option pricing first explored by boyle 1977 is often a useful method of estimating option prices the monte carlo method tends to be expensive and is often too time consuming for real time applications this study examines a simple method of approximat

the effect of slack diversification and time to recall on stock market reaction to toy recalls abstract past toy recalls have led to an increase in consumer concerns while toy manufacturers and retailers increasingly outsource and create longer supply chains making it more challenging for them to ensure toy safety this article examines firms making toy recall announcements to assess the impact operational characteristics have on the negative stock market reaction to the announcement 135 toy recall announcements in the u s from 1979 to 2016 were analyzed using event study and cross sectional regression while a toy recall announcement results in a negative stock market reaction our results show that greater levels of business diversification inventory slack and a longer time to recall are all associated with a less negative stock market reaction in contrast greater capacity slack is associated with a more negative stock market reaction we find no evidence that geographic diversification or financial slack influences the stock market reaction nor have reactions changed appreciably over time this article contributes to the product harm and product recall literature by focusing on these operational elements managers should be aware of the benefits of greater slack and business diversification while planning their business and the impact of a longer time to recall

a bayesian approach to modeling stock return volatility for option valuation new measures of stock return volatility are developed to increase the precision of stock option price estimates with bayesian statistical methods volatility estimates for a given stock are developed using prior information on the cross sectional patterns in return volatil ities for groups of stocks sorted on size financial leverage and trading volume call option values computed with the bayesian procedure generally improve prediction accuracy for market prices of call options relative to those computed using implied volatility standard historical volatility or even the actual ex post volatility that occurred during each option s life although the bayesian methods produce biased call price estimators they do reduce the systematic tendency of standard pricing approaches to overprice underprice options on high low volatility stocks little bias improvement is observed with respect to the time to maturity and moneyness of the call options

the pricing of options on assets with stochastic volatilities one option pricing problem that has hitherto been unsolved is the pricing of a european call on an asset that has a stochastic volatility this paper examines this problem the option price is determined in series form for the case in which the stochastic volatility is independent of the stock price numerical solutions are also produced for the case in which the volatility is correlated with the stock price it is found that the black scholes price frequently overprices options and that the degree of overpricing increases with the time to maturity one option pricing problem that has hitherto remained unsolved is the pricing of a european call on a stock that has a stochastic volatility from the work of merton 12 garman 6 and cox ingersoll and ross 3 the differential equation that the option must satisfy is known the solution of this differential equation is independent of risk preferences if a the volatility is a traded asset or b the volatility is uncorrelated with aggregate consumption if either of these conditions holds the risk neutral valuation arguments of cox and ross 4 can be used in a straightfoward way this paper produces a solution in series form for the situation in which the stock price is instantaneously uncorrelated with the volatility we do not assume that the volatility is a traded asset also a constant correlation between the instantaneous rate of change of the volatility and the rate of change of aggregate consumption can be accommodated the option price is lower than the blackscholes b s 1 price when the option is close to being at the money and higher when it is deep in or deep out of the money the exercise prices for which overpricing by b s takes place are within about ten percent of the security price this is the range of exercise prices over which most option trading takes place so we may in general expect the b s price to overprice options this effect is exaggerated as the time to maturity increases one of the most surprising implications of this is that if the b s equation is used to determine the implied volatility of a near the money option the longer the time to maturity the lower the implied volatility numerical solutions for the case in which the volatility is correlated with the stock price are also examined the stochastic volatility problem has been examined by merton 13 geske 7 johnson 10 johnson and shanno 11 eisenberg 5 wiggins 16 and

competitiveness through management of diversity effects on stock price valuation this study s premise is that firms that can lower their costs and enhance their differentiation through the effective management of their human resources have a competitive advantage using data fr

the pricing of convexity risk and timedecay in options markets abstract option valuation formulas typically assume all risk can be eliminated in a continuously rebalanced hedge but convexity of the option pricing function and time decay cause risk in real world hedges we find strong evidence in stock options transactions data from periods 10 years apart that the market prices these risks there is a significant price effect associated with convexity that becomes larger immediately following a period of larger stock price movements although time decay is highly correlated with convexity a multiple regression including both factors shows it to have a significant independent effect the results from the two sample periods are highly consistent as are pre and post crash results from the year 1987

the weekend effect on the distribution of stock prices abstract evidence of weekend effects on the distribution of security returns suggests that returns are generated by a process operating closer to trading time rather than calendar time in contrast accumulation of interest over the weekend follows a calendar time process since both the variance of returns and the interest rate are important parameters of the black scholes option pricing model this paper suggests that the model be stated to account for this by utilizing a trading time variance and a calendar time interest rate empirical evidence indicates that this allows the model to better explain market option prices

hedging the risks from writing foreign currency options abstract this paper considers the ways in which banks and other financial institutions can hedge their risks when they write non exchange traded foreign currency options key factors affecting the performance of delta hedging are identified and hedging schemes involving the use of exchange traded options are analyzed the schemes are tested using both simulated data and data from trades on the philadelphia exchange between february 1983 and september 1984

the risk premium of volatility implicit in currency options this article provides an empirical investigation of the risk neutral variance process and the market price of variance risk implied in the foreign currency options market there are three principal contributions first the parameters of heston s mean reverting square root stochastic volatility model are estimated using dollar mark option prices from 1987 to 1992 second it is shown that these implied parameters can be combined with historical moments of the dollar mark exchange rate to deduce an estimate of the market price of variance risk these estimates are found to be nonzero time varying and of sufficient magnitude to imply that the compensation for variance risk is a significant component of the risk premia in the currency market finally the out of sample test suggests that the historical variance and the hull and white implied variance contain no more information than that imbedded in the heston implied variance

market failure government failure and the private supply of public goods the case of climate controlled walkway networks two opposing models of public goods undersupply are those of market failure and government failure empirical work on the relative explanatory power of these two frameworks has been limited by the scarcity of acceptable data the case of climate controlled walkways in major urban cores is a rare instance where such difficulties can be overcome we investigate the supply of ccws in 55 large city cores in north america we find that 1 ccw networks are well supplied by market forces when 2 such forces are not frustrated by government policy we also find evidence that 3 rules based regimes dominate discretion based regimes these results are consistent with the position that the government failure paradigm is a viable alternative to the traditional market failure paradigm

the relative performance of five alternative warrant pricing models five warrant pricing models are examined in this study a pair based on the black scholes model a pair based on the constant elasticity of variance cev modification and an extendible warrant model a la longstaff based on more than 20 000 warrant price observations the flexible exponent cev model generates the lowest average absolute pricing error in most of the warrants examined the dilution adjusted black scholes model however remains a reasonable economical alternative in many cases

the corporate social responsibility of pharmaceutical product recalls an empirical examination of u s and u k markets the pressure on companies to practice corporate social responsibility csr has gained momentum in recent times as a means of sustaining competitive advantage in business the pharmaceutical industry has been acutely affected by this trend while pharmaceutical product recalls have become rampant and increased dramatically in recent years no comprehensive study has been conducted to study the effects of announcements of recalls on the shareholder returns of pharmaceutical companies as product recalls could significantly damage a company s reputation profitability and brand integrity this paper investigates the effect on shareholder wealth and the extent to which the adoption of csr practices by pharmaceutical companies in the united kingdom u k and the united states u s the two largest markets for pharmaceutical products in the world affected market reactions surrounding product recall announcements the analysis of product recall announcements from 1998 to 2004 compiled from the pharmaceutical journal and u s food and drug administration enforcement reports revealed marked differences in the way market participants in the two countries responded to news of product recalls u s investors penalised firms according to the severity of product defects while u k investors were indifferent while u k investors rewarded product recalls by firms which were not usually csr active u s investors punished non csr active firms that performed recalls these observations could pose strategic challenges to pharmaceutical firms operating in both countries

option pricing when the variance is changing the monte carlo method is used to solve for the price of a call when the variance is changing stochastically

time varying volatilities and calculation of the weighted implied standard deviation rogalski tinic have reported a monthly pattern in ex post stock return variances that differs between small and large market capitalization firms maloney rogalski find that option prices reflect these monthly patterns ex ante this study extends maloney rogalski s work by devising an expiration specific weighted implied standard deviation wisd it is found that i the monthly patterns in one month wisds are basically similar to the monthly patterns in ex post variances detected by rogalski tinic for both large and small size firms and ii use of expiration specific wisds as opposed to standard composite wisds results in improved performance of option pricing models

corporate environmental initiatives in the chinese context performance implications and contextual factors although a number of studies have been conducted on the relationship between environmental management and firm performance most of them are conducted in the western context due to the unique social and economic environments in china the performance implications of environmental management might be quite different in the chinese context we examine the impact of corporate environmental initiatives ceis on the market value of firms in china we find that in contrast to the findings in the western context chinese investors react negatively to cei announcements the negative reaction is more significant when the announcements are related to processes rather than products and for state owned enterprises rather than privately owned corporations however there is no difference whether the cei is self declared or third party endorsed overall our research indicates that chinese investors consider ceis to be in conflict with shareholder interest in particular ceis in state owned enterprises might be considered by investors as signals that firms need to sacrifice profits to shoulder more social responsibility

market incentives for safe foods an examination of shareholder losses from meat and poultry recalls meat and poultry recalls while voluntary are carried out under governmental oversight if firms have financial incentives to avoid being implicated in a recall situation governmental involvement in recalls may cause firms to internalize social costs when making investment decisions concerning food safety controls to examine these incentives we analyze federally supervised meat and poultry recalls from 1982 to 1998 within an event study results show significant shareholder losses when publicly traded food companies are implicated in a recall involving serious food safety hazards we find no evidence that the stock market reacts negatively when recalls involve less severe hazards each year unsafe foods sicken millions and lead to losses in terms of life and productivity mead et al estimate that foodborne pathogens account for 76 million illnesses and 5 000 deaths in the united states given human error and the limitations of food safety technology food items that pose undue risks to the public will be distributed from time to time when this occurs the firms involved stand to incur expenses related to recovering disposing of or reconditioning potentially contaminated products already placed on the market in addition negative publicity can lead to reductions in product demand and may erode prior investments in reputation and brand capital these firms may also face costs from liability claims associated with an outbreak of food related illnesses or injury our main objective in this paper is to examine reductions in food company valuations that result from food contamination incidents we focus specifically on meat and poultry firms that have shipped products that were later recalled for food safety reasons because preventative actions taken by firms can affect the probability of being implicated in a product recall situation the wealth that is lost when companies are required to recall

tests of an american option pricing model on the foreign currency options market this paper tests the ability of the american option pricing model proposed by parkinson 18 or mason 14 to explain the pricing of the foreign currency options traded on the philadelphia stock exchange from february 28 1983 to march 26 1985 we find that the model underprices out of the money options relative to at the money and in the money options this relative underpricing is driven by an underpricing of out of the money call options of short maturity in addition the degree of relative mispricing for most categories of options is shown to be a decreasing function of the time to maturity of the options longer maturity options appear to trade at similar levels of implied volatility whether they are in at or out of the money most of these biases appear consistent with the fact that the underlying spot currency rate follows a mixed jump diffusion process as described in 17

the impact of a product harm crisis on marketing effectiveness product harm crises are among a firm s worst nightmares a firm may experience i a loss in baseline sales ii a reduced own effectiveness for its marketing instruments iii an increased cross sensitivity to rival firms marketing mix activities and iv a decreased cross impact of its marketing mix instruments on the sales of competing unaffected brands we find that this quadruple jeopardy materialized in a case study of an australian product harm crisis faced by kraft peanut butter we arrive at this conclusion by using a time varying error correction model that quantifies the consequences of this crisis on base sales and on own and cross brand short and long term effectiveness the proposed modeling approach allows managers to make more informed decisions on how to regain the brands pre crisis performance levels

on the valuation of american call options on stocks with known dividends both the roll and the geske equations for the valuation of the american call option on a stock with known dividends are incorrectly specified this note presents the corrected valuation formula explains the misspecifications and provides a numerical example

the tylenol incident ensuing regulation and stock prices the much publicized tylenol incident in 1982 led to stringent packaging regulations for over the counter pharmaceutical drugs the sudden incident and the swift progression of associated events offer a unique opportunity to assess the wealth effects of the resultant regulations the market value of common stock of johnson johnson makers of tylenol declined by approximately 29 percent amounting to 2 31 billion although other firms in the industry also suffered significantly their share price decline did not occur around the tylenol incident but occurred around the subsequent packaging reg ulation proceedings on average 28 other pharmaceutical firms analyzed in this study experienced a decline of 310 million per firm or a total of about 8 68 billion the results suggest that the regulation had a significant negative effect on the common stock prices of firms in the pharmaceutical industry

event studies in management research theoretical and empirical issues we examined the use of event studies in management research and found that there was inadequate attention paid to theoretical and research design issues this lack of attention may lead to false in

foldvary fred public goods and private communities the market provision of social services brookfield vt ashgate publishing 1994 288 pp 59 95 do public goods and services such as streets parks and dams have to be provided by government in public goods and private communities fred foldvary s innovative application of public choice and social choice theory to questions of urban economics shows how collective goods can be provided by agents in a market process rejecting the market failure hypothesis dr foldvary argues that an entrepreneur can provide collective goods by consensual community agreements instead of studying particular services as previous studies have done this book concerns itself with entire private communities a series of case studies demonstrate how real world communities such as walt disney world the reston association in virginia and the private neighbourhoods of saint louis are in fact financing their own public goods and services in accordance with this theory for such communities to rise and prosper the author contends government must eliminate zoning and many other restrictions as well as the taxation of private services after considering the implications of his work for urban economies at a time when many of america s cities are plagued by decay violence and poverty dr foldvary argues that prosperity can be restored to cities if private communities are allowed to develop as an original response to an urgent contemporary problem this well written book will be welcomed by social scientists policy makers and business leaders seeking solutions to problems of urban decay

standard deviations implied in option prices as predictors of future stock price variability abstract standard deviations implied in option prices have recently been introduced as being better than average predictors of future stock price variability this article specifically studies the predictive ability of implicit standard deviations taking into account the dividend problem and the problem of optimal weighting schemes of the standard deviations when there are several options on the same stock transaction data information was used to study the importance of non simultaneities in observing stock and option prices

the financial impact of product recall announcements in china abstract a product recall can be viewed as a firm s worst nightmare although the long term damage to brand equity and company reputation may be difficult if not impossible to quantify the short term impact on shareholders wealth is readily estimable while many studies have examined this issue in the western context little is known about the financial impact of a product recall announcement in china to advance the knowledge about the financial impact of a product recall announcement we explore this issue using event study methodology in general our findings are congruent with previous research that product recalls result in negative abnormal returns interestingly however we found that chinese companies suffered from greater financial losses than their western counterparts did this study also provides evidence that the chinese food industry experiences a more severe stock market reaction than the automobile industry and that a passive recall strategy was associated with a more negative stock market reaction than a proactive recall strategy we conclude with several future research avenues for global research on product recalls

the liability of good reputation a study of product recalls in the u s automobile industry in this paper we explore opposing theoretical claims about how organizational reputation affects market reactions to product defects on the one hand good reputation could be a disadvantage because expectations about product quality are more likely to be violated by defects in highly reputed products on the other hand a good reputation could be an advantage because of strong inertial effects on reputation orderings we empirically test these competing hypotheses using data on product recalls in the u s automobile industry from 1975 to 1999 our results support for the idea that reputation can be an organizational liability in that highly reputed firms suffer more market penalty as a result of their product recalls we also propose that the reputational effects are moderated by two important factors substitutability and generalism specialism our results show that having few substitutes with an equivalent level of reputation or a focused product identity stemming from specialism buffers the negative market reactions to product recalls we conclude with a discussion on the implications of these results for institutional reputation and status theories

valuation of american call options on dividend paying stocks empirical tests abstract this paper examines the pricing performance of the valuation equation for american call options on stocks with known dividends and compares it with two suggested approximation methods the approximation obtained by substituting the stock price net of the present value of the escrowed dividends into the black scholes model is shown to induce spurious correlation between prediction error and 1 the standard deviation of stock return 2 the degree to which the option is in the money or out of the money 3 the probability of early exercise 4 the time to expiration of the option and 5 the dividend yield of the stock a new method of examining option market efficiency is developed and tested

the systematic risk of discretely rebalanced option hedges this paper demonstrates that black scholes option pricing model hedge positions that are risk free when rebalanced continuously will frequently exhibit substantial systematic risk when rebalanced at finite intervals this systematic risk may have biased important empir ical tests of the option pricing model moreover this systematic risk means that the blackscholes option pricing model is inherently inconsistent with the discrete time version of the capital asset pricing model capm