银行间债券市场含权债估值问题研究

文章分析了银行间市场含权债实际成交价格的变动规律,介绍了市场实践中常用的定价方法,并对以理论模型为基础的一般估值方法进行了研究。结果发现,虽然目前市场上含权债的交易价格基本合理,但估值实践中较少利用理论模型,一般参考市价简单处理。含权债定价可以从建立二项式模型开始,逐步改变目前市场定价随意、缺少理论支撑的现状。     

Binomial Option Pricing Biases and Inconsistent Implied Volatilities

We evaluate the binomial option pricing methodology (OPM) by examining simulated portfolio strategies. A key aspect of our study involves sampling from the empirical distribution of observed equity returns. Using a Monte Carlo simulation, we generate equity prices under known volatility and return parameters. We price American–style put options on the equity and evaluate the risk–adjusted performance of various strategies that require writing put options with different maturities and moneyness characteristics. The performance of these strategies is compared to an alternative strategy of investing in the underlying equity. The relative performance of the strategies allows us to identify biases in the binomial OPM leading to the well–known volatility smile . By adjusting option prices so as to rule out dominated option strategies in a mean–variance context, we are able to reduce the pricing errors of the OPM with respect to option prices obtained from the LIFFE. Our results suggest that a simple recalibration of inputs may improve binomial OPM performance.     

不确定性下创意企业价值评估分析

文章从产品产业化过程的角度出发对创意产业企业不确定性进行了分析,归纳出创意产业企业的不确定性来源。鉴于不确定性的复杂性和创意产业的实物期权特征,以及对企业价值评估模型的讨论,改进了Schwartz-Moon期权模型,对创意产业企业价值进行评估。从连续时间和离散时间两种情况出发,构建了创意产业企业预期收入与企业现金流模型,在此基础上,讨论了可变成本、产权收入和公司产品的价值损失三个变量与创意产业的企业价值的关系,并在考虑税率的情况下构建企业税后净收入模型以全面考察创意产业企业价值。     

实物期权在项目信贷评估中的运用

近20年来,众多国内外学者对实物期权进行了大量研究并得出结论:决策灵活性确实增加了项目整体评估价值。但这些研究基本上是从项目管理者角度进行分析的。本文着重从银行角度探讨了实物期权在信贷评估过程中的作用,结果表明:在传统的以折现现金流法(DiscountedCashFlow,DCF)为主导的项目评估过程中融入实物期权思想,将使对高科技类项目的评价更加客观、全面。对项目投资决策选择权的分析可以加强信贷工作人员对项目贷款风险趋势的事前判断,对项目在未来运行中的不确定性进行评估,并通过在合同中增加约束性条款,实现项目权利向银行权利的转化,以降低银行信贷风险。     

Companies' Modest Claims About the Value of CEO Stock Option Awards

This paper analyzes company disclosures of CEO stock option values in compliance with the SEC's regulations for reporting executive compensation data to stockholders. Companies appear to exploit the flexibility of the regulations to reduce the apparent value of managerial compensation. Companies shorten the expected lives of stock options and unilaterally apply discounts to the Black-Scholes formula. Theoretical support for these adjustments is often thin, and companies universally ignore reasons that the Black-Scholes formula might underestimate the value of executive stock options. The findings not only cast light upon how corporations value executive stock options, but also provide a means of forecasting compliance with controversial new FASB requirements for firms to disclose the compensation expense represented by executive stock options.     

Binomial option pricing with stochastic parameters: A beta distribution approach

This research extends the binomial option-pricing model of Cox, Ross, and Rubinstein (1979) and Rendleman and Barter (1979) to the case where the up and down percentage changes of stock prices are stochastic. Assuming stochastic parameters in the discrete-time binomial option pricing is analogous to assuming stochastic volatility in the continuous-time option pricing. By assuming that the up and down parameters are independent random variables following beta distributions, we are able to derive a closed-form solution to this stochastic discrete-time option pricing. We also derive an upper and a lower bounds of the option price.     

Valuation of Callable Warrants

A simple valuation model for callable warrants is derived and tested. The model is expressed in closed form except for one term which can be evaluated numerically. Predictions of 78 warrant prices are compared to market prices and the average error is -.224 percent. By contrast, the Black-Scholes model applied to the same warrants produces an average error of 31.44 percent. Thus the callability feature cannot safely be ignored in determining warrant values.     

On Pricing Exponential Square Root Barrier Knockout European Options

A barrier option is one of the most popular exotic options which is designedto give a protection against unexpected wild fluctuation of stock prices.Protection is given to both the writer and holder of such an option.Kunitomo and Ikeda (1992) analytically obtained a pricing formula forexponential double barrier knockout options. Since the logarithm of theirproposed barriers for the stock price process S(t), whichisassumed to be geometric Brownian motion, are nothing but straight lineboundaries, the protection provided by them is not uniform over time. Toremedy this problem, we propose square root curved boundaries±btfor the underlying Brownian motion process W(t). Since thestandarddeviation of Brownian motion is proportional to t, theseboundaries(after transformation) can be made to provide more uniform protectionthroughout the life time of the option. We will apply asymptoticexpansions of certain conditional probabilities obtained by Morimoto (1999)to approximate pricing formulae for exponential square root double barrierknockout European call options. These formulae allow us to computenumerical values in a very short time (t < 10^–6sec), whereas it takesmuch longer to perform Monte Carlo simulations to determine optionpremiums.     

The Effect of Exercise Date Uncertainty on Employee Stock Option Value

The IASC recently recommended that employee compensation in the form of stock options be measured at the 'fair value' based on an option pricing model and the value should be recognized in financial statements. This follows adoption of SFAS No. 123 in the United States, which requires firms to estimate the value of employee stock options using either a Black‐Scholes or binomial model. Most US firms used the B‐S model for their 1996 financial statements. This study assumes that option life follows a Gamma distribution, allowing the variance of option life to be separate from its expected life. The results indicate the adjusted Black‐Scholes model could overvalue employee stock options on the grant date by as much as 72 percent for nondividend paying firms and by as much as 84 percent for dividend paying firms. The results further demonstrate the sensitivity of ESO values to the volatility of the expected option life, a parameter that the B‐S model or a Poisson process cannot accommodate. The variability of option life has an especially big impact on ESO value for firms whose ESOs have a relatively short life (5 years, for example) and high employee turnover. For such firms, the results indicate a binomial option pricing model is more appropriate for estimating ESO value than the B‐S type model.     

Bias in an Empirical Approach to Determining Bond and Mortgage Risk Premiums

Empirical studies of bond and commercial mortgage performance often quantify a required risk premium by examining the difference between the promised yield and the realized yield as adjusted for default occurrence. These studies omit the effects of various other sources of risk, however, including collateral asset market risk, interest rate risk, and possibly call risk. These omissions downwardly bias the empirical risk premium estimate on the debt. In this paper, we disentangle and quantify the sources of this bias by modeling secured coupon debt (the commercial mortgage) as used in the calculation of a realized investment return. We consider deterministic and stochastic interest rate economies with mortgage contracts that are either noncallable or subject to a temporary prepayment lockout period. Given realistic parameter values associated with the term structure, underlying asset dynamics, and debt contracting, we show that the magnitude of the bias can be significant.