Comparative empirical study of binomial call-option pricing methods using S&P 500 index data

In this paper, several binomial models are tested empirically on S&P500 Index on the levels of tradability, proximity to market (RMS) prices and profitability, especially close to expiration day. These comparisons will be carried out for many different business environments, including different market trends and moneyness levels traded. Among the models under analysis we assess the quality of the SH model, developed by the authors in previous work, in relation to other models. The option price in the SH model is affected by the players’ assessments about the behavior of the prices of the underlying asset up to the expiration day and by their “eagerness” levels (i.e., players’ readiness to respond to a given bid proposed by their opponent). We found that for all models, the higher the moneyness, the greater the proximity of models prices to actual market prices and that, eagerness parameters have a decisive effect on tradability. We also found that there was no correlation between the degree of proximity of modeled prices to actual prices and the expected profit gained by players that act according to a given model and that the SH model traded relatively small number of options. The expected profit is highest for the SH model in the ITM and ATM for days that are far from the expiration day.     

S&P 500 futures market and the normal backwardation hypothesis

This paper examines the behavior of near term S&P 500 index futures contract prices in the context of the theory of normal backwardation. Daily S&P 500 futures prices for 41 contracts over the 1982–1992 period are examined. There is no evidence that S&P 500 futures prices are biased estimates of the expected future spot price on expiration. Daily futures prices usually lie below the expected future spot price on expiration and usually rise over the contract period, but these price movements are not statistically significant. The surprising result of this study is the number of observations where backwardation appears not to hold. Furthermore, changes in the U.S. dollar exchange rates, the Tax Reform Act of 1986 and the switching of S&P 500 contracts quarterly expiration day had no significant effect on the behavior of S&P 500 futures prices.     

Implied volatility and the risk-free rate of return in options markets

We numerically solve systems of Black–Scholes formulas for implied volatility and implied risk-free rate of return. After using a seemingly unrelated regressions (SUR) model to obtain point estimates for implied volatility and implied risk-free rate, the options are re-priced using these parameters. After repricing, the difference between the market price and model price is increasing in time to expiration, while the effect of moneyness and the bid-ask spread are ambiguous. Our varying risk-free rate model yields Black–Scholes prices closer to market prices than the fixed risk-free rate model. In addition, our model is better for predicting future evolutions in model-free implied volatility as measured by the VIX.     

Dynamic competition with consumer inertia

We study a framework where two duopolists compete repeatedly in prices and where chosen prices potentially affect future market shares, but certainly do not affect current sales. This assumption of consumer inertia causes (noncooperative) coordination on high prices only to be possible as an equilibrium for low values of the discount factor. High discount factors increase opportunism and aggressiveness of competition to such an extent that high prices are no longer sustainable as an equilibrium outcome. Moreover, we find that both monopolization and enduring market share and price fluctuations (price wars) can be equilibrium path phenomena without requiring exogenous shocks in market or firm characteristics.     

Option pricing and replication with transaction costs and dividends

This paper derives optimal perfect hedging portfolios in the presence of transaction costs within the binomial model of stock returns, for a market maker that establishes bid and ask prices for American call options on stocks paying dividends prior to expiration. It is shown that, while the option holder's optimal exercise policy at the ex-dividend date varies according to the stock price, there are intervals of values for such a price where the optimal policy would depend on the holder's preferences. Nonetheless, the perfect hedging assumption still allows the derivation of optimal hedging portfolios for both long and short positions of a market maker on the option.     

Technological change in health care: Why are opinions so divided?

This paper purports to explain the widespread scepticism towards technological change in health care in general and pharmaceutical innovation in particular in the face of very high estimated rates of social return. These estimates are based on observable market prices and quantities, which are used for measuring the additional consumer surplus induced by an innovation. They grossly overstate true surplus due to the effect of insurance, however. For true demand for health care services and hence true surplus depends on the net price a patient is willing to pay, which is a rather small fraction of observed market price. The paper also outlines the conditions under which a health insurer would welcome a pharmaceutical innovation.     

Drug innovation and price competition

This study is designed to examine the relationship between drug innovation and price competition. The empirical results presented here support the hypothesis that new drugs-as measured by new chemical entities-exert downward pressure on the prices of existing competitors within the same therapeutic class. The implication of this finding for public policy is that drug innovation not only provides new therapy but also stimulates price competition.     

Cobweb dynamics and price dispersion in illicit drug markets

Extreme price dispersion is a hallmark of illegal drug markets, and this apparent contradiction to the law of one price has long puzzled drug market economists. We propose a novel explanation for this dispersion: the coupling of dealers’ unwillingness to hold inventory with dealers’ imperfect foresight concerning future prices and/or random lead times when “ordering” drugs from higher-level suppliers. Unwillingness to hold inventory means drug markets might operate consistent with a cobweb model. The classic cobweb model was inspired by the observation of cyclic (typically annual) fluctuations in commodity prices. However, with minor changes that make the model more realistic the resulting price trajectories can be highly variable or even chaotic, not just periodic. Cobweb dynamics can also amplify the variability created by supply chain disruptions.     

基于市盈率修正的非上市公司国有股权定价模型研究

外资并购国有企业对我国国有企业改革和资本市场的发展具有重要的推动作用,合理确定国有股的转让价是外资并购中的核心问题,它将直接影响到外资并购的成功与否。基于市盈率修正的非上市公司国有股权定价模型,根据恰当的指标采用德尔菲法选取上市公司作为参照公司,将非流通股和流通股区别定价,采用加权法确定上市公司合理市盈率,解决了直接利用流通股市盈率估价非流通股存在的市盈率易被高估的问题,完善了传统的股权定价理论,对非上市公司国有股权定价具有很好的指导作用。     

浅析药价调控

本文对于药品的经济学特征进行阐述,从而分析政府调控药价难的主要原因。并总结药价调控方法,提出可进一步加强的措施为政府有效的调控药品价格,防止药价失控提供借鉴意义。     

The effectiveness of price-stabilizing share buybacks: Evidence from listed firms in Vietnam

The majority of share buybacks in Vietnam involve the sole stated purpose of price stabilization. Using a sample of repurchases announced in 2008–2016 and control firms based on propensity score matching, we find the Vietnamese repurchases to be effective in stabilizing prices and enhancing liquidity. Utilizing the special disclosure features in Vietnam that allow clearly-defined sub-windows of pre-trading, trading, and post-trading, we further examine the different mechanisms of market reactions and actual firm buyback transactions in the buyback process. We document significantly higher abnormal returns over the pre-trading window driven by market reactions, and improved liquidity and reduced volatility over the firm’s actual transaction window for the buyback firms. We also report a significant moderating effect of target shares announced and actual shares repurchased depending on the sub-window under examination. We do not find any evidence of effectiveness in the post-trading window or over a longer-term beyond the buyback period.     

Should we worry about the decline of the public corporation? A brief survey of the economics and external effects of the stock market

In recent years, the number of listed companies has been declining in many countries across the world. This paper provides a selective survey of the literature on the real economic effects of the stock market to assess the potential effects of this decline and determine whether it is likely to continue. The leading economic role of the stock market’s primary market, in which firms raise capital by issuing new shares, is to help growing firms secure financing. We discuss providing and certifying information, coordinating investors, and easing the redeployment of capital as the means through which capital allocation can be efficiently achieved. The main economic roles of the stock market’s secondary market, the trade in existing shares, is to provide liquidity to shareholders, to aid in price discovery and to provide diversification opportunities. Positive external effects from an active stock market may arise for consumers, labor and private firms due to increased corporate investment, more socially responsible business strategies and a more positive business climate. Negative external effects on capital allocation and productivity can arise from short-termism, market mispricing, and increased cross-ownership. Local stock markets can spur innovation and foreign direct investment (FDI) and reduce the risk of early cross-border acquisitions. Given the myriad of useful economic functions the stock market performs, a future entirely absent of public companies is difficult to imagine and the decline is therefore likely at some point to come to an end. Whether we need to worry about the decline depends on the relative importance of the positive and negative external effects, a topic we feel warrants more research.     

The relationship between oil prices,the stock market and the exchange rate: Evidence from Mexico

This paper analyzes the variables of oil price, exchange rate and stock market index to explain how they interact with each other in the Mexican economy. The examined period includes monthly data from January 1992 to June 2017. A Vector Autoregressive Model (VAR) is implemented that includes oil prices, the nominal exchange rate, the Mexican stock market index, and the consumer price index. Results indicate that the exchange rate has a negative and statistically significant effect on the stock market index; this indicates that an appreciation of the exchange rate is related to an increase in the stock market index. It is also found that the consumer price index has a positive effect on the exchange rate and a negative effect on the stock market index. The results also indicate that oil prices are statistically significant against the exchange rate, concluding that an increase in oil prices creates an appreciation of the exchange rate. In addition, the impulse-response functions show that the effects found tend to disappear over time.     

Pricing-to-market in U.S. imports and exports: A time series and cross-sessional study

This paper provides a comparative study of how U.S. imports and exports prices react to exchange rate changes. It finds, through time series analyses, that while both U.S. and foreign exporters price to market, foreign exporters in general absorb a large portion of exchange rate changes by themselves while U.S. exporters pass through most of the exchange rate change to foreign currency prices. Pricing behavior of U.S. imports and, to a lesser extent, of U.S. exports varies across industries and such variation relates to industry characteristics such as market shares, product d differentiation, and capital-to-labor ratio.     

Leverage and the price volatility of equity shares in equilibrium

The traditional valuation formulas for corporate debt, which are derived in a complete market setting and are based on the no-arbitrage principle, imply that equity prices become more volatile as leverage increases. If the asset structure is incomplete, the presence of corporate debt affects the linear subspace spanned by the payoffs of the existing assets, and the pricing of corporate debt and shares of levered firms becomes a simultaneous valuation problem. This paper characterizes the relationship between the price of corporate debt and the share price of a levered firm in an equilibrium framework where corporate debt is a non-redundant asset. While, in the absence of bankruptcy, higher leverage always implies riskier equity, it does not necessarily mean more volatile equity prices. In fact, the link between leverage and equity price volatility depends in a particular way on investors’ preferences towards risk.     

Entry limiting agreements: First‐mover advantage,authorized generics,and pay‐for‐delay deals

During patent litigation, pay‐for‐delay (P4D) deals involve a payment from a patent holder of a branded drug to a generic drug manufacturer to delay entry and withdraw the patent challenge. In return for staying out of the market, the generic firm receives a payment, and/or an authorized licensed entry at a later date, but before the patent expiration. We examine why such deals are stable when there are multiple potential entrants. We combine the first‐mover advantage for the first generic with the ability of the branded manufacturer to launch an authorized generic (AG) to show when P4D deals are an equilibrium outcome. We further show that limiting a branded firm's ability to launch an AG before entry by a successful challenger will deter such deals. However, removing exclusivity period for the first generic challenger will not.     

Welfare improving licensing with endogenous choice of prices versus quantities

This paper investigates the endogenous choice of prices versus quantities by taking into account patent licensing where the patent holder, which is itself a producer within the industry, licenses its cost-reducing innovation to the rival firm through a two-part tariff contract. For substitute products we find that both Cournot and mixed price-quantity competition may constitute the equilibrium outcomes, depending on the innovation size. Contrary to the results in Fauli-Oller and Sandonis (2002), we show that the optimal licensing contract definitely leads to an increase in social welfare. Our result reinforces the positive welfare effect of patent licensing.     

SPAC融资模式的股价长期弱势效应——基于奥瑞金种业上市NASDAQ的实证研究

本文通过CAR模型分析了SPAC模式上市公司股价长期弱势的特点,并且运用多元回归分析的方法来探寻影响公司股价长期弱势的因素。结果表明,在SPAC融资机制的特殊性中,SPAC投资者的投资收益率减小而引起的套利性增大是股价长期弱势的重要原因。同时,企业经营业绩也是股价长期弱势的关键因素。而市场性因素虽然对股价长期弱势影响不显著,但也抑制了股价的转向强势的可能性。