The effects of taxation on put‐call parity

Share and option transactions are taxed differently, which means that the after‐tax cash flows used to establish put‐call parity will differ depending on which option is exercised. This paper derives the after‐tax put‐call parity relationship for European and American options with or without dividends. Using Australian data for the period July 1999 to June 2002, the after‐tax put‐call parity relationship explains 88.3 per cent of no‐tax lower boundary violations and 78.8 per cent of no‐tax upper boundary violations. The violation are larger for more thinly traded securities, providing some evidence that traders are able to profit from the tax discontinuities that affect investors in options.     

An offer you can't refuse: early contracting with endogenous threat

A seller has private information on the future gains from trade with a buyer, but the buyer has the option to invest to produce the good internally. Both the buyer and the seller can efficiently trade ex post under complete information. Despite the lack of information, the buyer sometimes gains by making an early contract offer to the seller. The early contract divides the different types of sellers according to their information, which renders the threat of producing the good in‐house credible and enables the buyer to extract a larger share of the gains from trade. Several extensions are investigated.     

EARLY EXERCISE OF AMERICAN INDEX OPTIONS

We show that exercise of American call options on stock indexes frequently occurs before expiration and attribute this early exercise to the “wild card” option that results from the cash settlement exercise process. The wild card represents an “implied option” to sell the index option at the fixed settlement price; it is therefore a put option on the index call option. We derive a simple one-period valuation model using compound option pricing. Analysis of observed early exercise demonstrates that the wild card feature is a factor influencing early exercise of index options.     

Confined exponential approximations for the valuation of American options

We provide an alternative analytic approximation for the value of an American option using a confined exponential distribution with tight upper bounds. This is an extension of the Geske and Johnson compound option approach and the Ho et al. exponential extrapolation method. Use of a perpetual American put value, and then a European put with high input volatility is suggested in order to provide a tighter upper bound for an American put price than simply the exercise price. Numerical results show that the new method not only overcomes the deficiencies in existing two-point extrapolation methods for long-term options but also further improves pricing accuracy for short-term options, which may substitute adequately for numerical solutions. As an extension, an analytic approximation is presented for a two-factor American call option.     

商业银行贷款定价行为与房地产价格泡沫

房地产信贷是基于潜在资产的看跌期权,贷款人是卖方,借款人是买方。贷款人对看跌期权价值的低估会导致资产价格膨胀、偏离基础价值,而银行家和股东均存在低估看跌期权的正向激励。开放经济条件下,贷款利率、存款利率与汇率三个因素增加资产市场价格与基础价值的差距。基于对PW模型的扩展分析,中国2005年7月至2007年12月的数据也证实了房地产价格与利差和汇率负相关,与存款利率正相关。     

Pricing derivatives of American and game type in incomplete markets

In this paper the neutral valuation approach is applied to American and game options in incomplete markets. Neutral prices occur if investors are utility maximizers and if derivative supply and demand are balanced. Game contingent claims are derivative contracts that can be terminated by both counterparties at any time before expiration. They generalize American options where this right is limited to the buyer of the claim. It turns out that as in the complete case, the price process of American and game contingent claims corresponds to a Snell envelope or to the value of a Dynkin game, respectively.On the technical level, an important role is played by -sub- and -supermartingales. We characterize these processes in terms of semimartingale characteristics.Received: June 2003, Mathematics Subject Classification (2000):   91B24, 60G48, 91B16, 91A15, 60G40JEL Classification:   G13, D52, C73The authors want to thank PD Dr. Martin Beibel for the idea leading to the proof of Proposition A.4 and both anonymous referees for many valuable comments. The second author gratefully acknowledges financial support by the Deutsche Forschungsgemeinschaft through the Graduiertenkolleg Angewandte Algorithmische Mathematik at Munich University of Technology and by the Fonds zur Förderung der wissenschaftlichen Forschung at Vienna University of Technology.     

Pricing equity options everywhere

Finite difference methods are a popular technique for pricing American options. Since their introduction to finance by Brennan and Schwartz their use has spread from vanilla calls and puts on one stock to path-dependent and exotic options on multiple assets. Despite the breadth of the problems they have been applied to, and the increased sophistication of some of the newer techniques, most approaches to pricing equity options have not adequately addressed the issues of unbounded computational domains and divergent diffusion coefficients. In this article it is shown that these two problems are related and can be overcome using multiple grids. This new technique allows options to be priced for all values of the underlying, and is illustrated using standard put options and the call on the maximum of two stocks. For the latter contract, I also derive a characterization of the asymptotic continuation region in terms of a one-dimensional option pricing problem, and give analytic formulae for the perpetual case.     

Real options with ex-post division of the surplus

This paper examines a real option model where two vertically related firms are involved in a specific investment project that is subject to an uncertain payoff. While ex-post bargaining between a seller and a buyer leads to underinvestment by the seller in a standard model where timing of the seller’s investment is exogenous, we show that this need not be the case when the seller’s timing of investment is endogenous. However, bargaining with a buyer leads to excessive waiting. More severe holdup and higher uncertainty will lead to vertical integration of activities to avoid timing inefficiencies.     

Is the information obtained from European options on equally weighted baskets enough to determine the prices of exotic derivatives such as worst-of options?

In recent years there has been a remarkable growth of multi-asset options. These options exhibit sensitivity to the volatility of the underlying assets, as well as to their correlations. The call versus call is a product commonly used to trade correlation within the inter-dealer broker markets. The buyer of correlation buys a European call on the equally weighted basket option and sells a weighted average of European calls on each asset. In this case, the following important question arises: Is the information provided by equally weighted basket options enough to price other European multi-asset exotic derivatives such as worst-of or outperformance options? This article investigates this issue under a stochastic correlation framework. Importantly, this article shows that, when pricing multi-asset exotic derivatives, matching the prices of European equally weighted basket options, quoted in the market, does not guaranty the absence of model risk even in the case where the exotic payoff is observed only at maturity.     

American option pricing under the double Heston model based on asymptotic expansion

This paper focuses on pricing American put options under the double Heston model proposed by Christoffersen et al. By introducing an explicit exercise rule, we obtain the asymptotic expansion of the solution to the partial differential equation for pricing American put options. We calculate American option price by the sum of the European option price and the early exercise premium. The early exercise premium is calculated by the difference between the American and European option prices based on asymptotic expansions. The European option price is obtained by the efficient COS method. Based on the obtained American option price, the double Heston model is calibrated by minimizing the distance between model and market prices, which yields an optimization problem that is solved by a differential evolution algorithm combined with the Matlab function fmincon.m. Numerical results show that the pricing approach is fast and accurate. Empirical results show that the double Heston model has better performance in pricing short-maturity American put options and capturing the volatility term structure of American put options than the Heston model.     

金融双语信用违约互换

Credit default swaps can be thought of as an insurance against the default of some underlying instrument1, or as a put option on the underlying instrument. In a typical credit default swap, as shown in figure, the party selling the credit risk (or the "protection buyer") makes periodic payments to the "protection seller" of a negotiated number of basis points , times the notional amount of the underlying bond or loan.     

The GARCH Option Pricing Model: A Modification of Lattice Approach

Ritchken and Trevor (1999) proposed a lattice approach for pricing American options under discrete time-varying volatility GARCH frameworks. Even though the lattice approach worked well for the pricing of the GARCH options, it was inappropriate when the option price was computed on the lattice using standard backward recursive procedures, even if the concepts of Cakici and Topyan (2000) were incorporated. This paper shows how to correct the deficiency and that with our adjustment, the lattice method performs properly for option pricing under the GARCH process. JEL Classification: C10, C32, C51, F37, G12     

Robust pricing with refunds

Before purchase, a buyer of an experience good learns about the product's fit using various information sources, including some of which the seller may be unaware of. The buyer, however, can conclusively learn the fit only after purchasing and trying out the product. We show that the seller can use a simple mechanism to take best advantage of the buyer's post-purchase learning to maximize his guaranteed-profit. We show that this mechanism combines a generous refund, which performs well when the buyer is relatively informed, with non-refundable random discounts, which work well when the buyer is relatively uninformed.     

Biases in option prices : Evidence from the foreign currency option market

This paper examines a European call model of option pricing over a data set which does not suffer from the early exercise problems that have plagued earlier studies of call options on common stocks. We specifically examine a data set of American call prices on spot foreign exchange for which it is plausible to apply an adjusted version of the Garman-Kohlhagen (1983) and Grabbe (1983) European call option model. We make adjustments for interest rate risk and find that the model is nearly unbiased in the valuation of foreign currency options. We conclude that the Geske-Roll (1984) conjecture about dividend uncertainty creating biases in stock option prices holds analogously in the foreign currency option market. Interest rate differential risk (analogous to risky dividends) thus appears to be an important element in the valuation of foreign currency options.     

On the Robustness of Least-Squares Monte Carlo (LSM) for Pricing American Derivatives

This paper analyses the robustness of Least-Squares Monte Carlo, a technique proposed by Longstaff and Schwartz (2001) for pricing American options. This method is based on least-squares regressions in which the explanatory variables are certain polynomial functions. We analyze the impact of different basis functions on option prices. Numerical results for American put options show that this approach is quite robust to the choice of basis functions. For more complex derivatives, this choice can slightly affect option prices. This revised version was published online in June 2006 with corrections to the Cover Date.