Intermarket efficiency: An application of interbattery APT to mortgage-backed securities

Increasing popularity of investments in mortgage-backed securities has led to closer integration of the mortgage market into traditional capital markets. Using monthly returns during 1982–1988 for common stocks, Treasury bonds and GNMA and FHLMC mortgage-backed securities, the interbattery factor analytic Arbitrage Pricing Theory of (Cho, 1984) is used to test five hypotheses for intramarket and intermarket integration. Results indicate that three to five common factors are found within the same security market, while only one to three factors are found common between different markets.The APT could not be rejected within the same security market, but was rejected in most intermarket comparisons. While risk-free rates are found to differ between markets, the risk premium tests are conclusive indicators of integration. Our results support claims that the stock, bond, and the mortgage-backed securities markets are integrated.     

Reputations and credit ratings: Evidence from commercial mortgage-backed securities

How do changes in a rating agency's reputation affect the ratings market? We study the dynamics of credit ratings after Standard & Poor's (S&P) was shut out of a large segment of the commercial mortgage-backed securities (CMBS) ratings market following a procedural mistake. Exploiting the fact that most CMBS have ratings from multiple agencies, we show that S&P subsequently eased its standards compared to other raters. This coincided with a partial recovery in the number of deals S&P was hired to rate. Our findings suggest that an agency can regain market share after suffering reputational damage by issuing optimistic ratings.     

A note on refinancing costs,prepayment assumptions,and the value of mortgage-backed securities

This article analyzes the effect and timing of the FHA's streamline refinance program on the value of GNMA 15s. The program announced in March 1989 reduced the refinancing costs for those mortgages of 15 percent and above. The program is expected to reduce the value of GNMA's. The authors find a reduction of .47 to 3.40 points in the value of GNMA 15s during the 3-week to 13-week period following the announcement of the plan. The drop in value translates into a wealth loss for GNMA 15 holders of about $20 million over this time.     

The information content of three credit ratings: the case of European residential mortgage-backed securities

We assess the information content of three credit ratings for tranches of newly issued European residential mortgage-backed securities. We find that tranches rated by three credit rating agencies where the rating by Standard & Poor's (S&P's) Ratings Service or Fitch is inferior to Moody's lead to higher funding costs and reflects what we refer to as rating risk. Our results suggest that market participants do not view credit ratings by Fitch and S&P's as redundant despite the fact that both employ the same rating approach.     

Option Pricing Bounds and the Elasticity of the Pricing Kernel

In this paper we use power functions as pricing kernels to derive option-pricing bounds. We derive option pricing bounds given the bounds of the elasticity of the true pricing kernel. The bounds of the elasticity of the true pricing kernel are closely related to the bounds of the representative investor's coefficient of relative risk aversion. This methodology produces a tighter upper call option bound than traditional approaches. As a special case we show how to use the Black–Scholes formula to obtain option pricing bounds under the assumption of lognormality.     

公司价值理论与股票定价

经济金融化使现代公司财务理论从以往的边缘地位逐步朝着金融经济学的核心与主流方向发展。公司价值理论作为现代公司财务伯重要组成部分已日臻完善和成熟。我国长期对公司价值理论研究的忽视，不仅是企业落后的深层原因，而且也是影响市场发展重要因素之一，因为股票价值与公司价值直接相关，忽视公司价值而形成的股票价格不仅是不合理的，而且会对股票市场产生不良影响。     

Pricing mortgage-backed securities in a multifactor interest rate environment: a multivariate density estimation approach

Multivariate density estimation (MDE) suggests that mortgage-backedsecurity (MBS) prices can be well described as a function ofthe level and slope of the term structure. We analyze how thisfunction varies across MBSs with different coupons. An importantfinding is that the interest rate level proxies for the moneynessof the option, the expected level of prepayments, and the averagelife of the cash flows, while the term structure slope controlsfor the average rate at which these cash flows should be discounted.     

Rational prepayment and the valuation of mortgage-backed securities

This article presents a new model of mortgage prepayments, basedon rational decisions by mortgage holders. These mortgage holdersface heterogeneous transaction costs, which are explicitly modeled.The model is estimated using a version of Hansen's (1982) generalizedmethod of moments, and is shown to capture many of the empiricalfeatures of mortgage prepayment. Estimation results indicatethat mortgage holders act as though they face transaction coststhat far exceed the explicit costs usually incurred on refinancing.They also wait an average of more than a year before refinancing,even when it is optimal to do so. The model fits observed prepaymentbehavior as well as the recent empirical model of Schwartz andTorous (1989). Implications for pricing mortgage-backed securitiesare discussed.     

基于蒙特卡罗模拟的多标的资产期权定价研究

在单标的资产价格随机模型的基础上,推导了具相关性的多标的资产价格的随机过程公式,以此构造蒙特卡罗模拟高维欧式期权定价的随机模型,给出模拟算法,并分析了影响蒙特卡罗模拟效果的几个关键因素。模拟算例的结果显示模拟效果较好。     

Pricing the Chicago Board of Trade T-Bond futures

The aim of this paper is to investigate the pricing of the Chicago Board of Trade (CBOT) Treasury-Bond futures. The difficulty in pricing it arises from its multiple inter-dependent embedded delivery options, which can be exercised at various times and dates during the delivery month. We consider a general Markov diffusion process model for stochastic interest rates and propose a pricing algorithm that can handle all the delivery rules embedded in the CBOT T-Bond futures. Our procedure combines dynamic programming, finite-elements approximation, and fixed-point evaluation. Numerical illustrations are provided under the one-factor Vasicek and Cox–Ingesoll–Ross models, and under the time in-homogeneous Hull–White model.     

Pricing jump risk with utility indifference

This paper is concerned with option pricing in an incomplete market driven by a jump-diffusion process. We price options according to the principle of utility indifference. Our main contribution is an efficient multi-nomial tree method for computing the utility indifference prices for both European and American options. Moreover, we conduct an extensive numerical study to examine how the indifference prices vary in response to changes in the major model parameters. It is shown that the model reproduces ‘crash-o-phobia’ and other features of market prices of options. In addition, we find that the volatility smile generated by the model corresponds to a zero mean jump size, while the volatility skew corresponds to a negative mean jump size.     

Pricing dynamic binary variables and their derivatives

Many important assets or business ventures have cash flows that are not derivatives of a market security but are nevertheless dependent on some variable that is correlated with market prices. This includes many real option projects. This paper presents a methodology using a binary framework for pricing such assets by projection onto the market space. Under certain conditions, the result has the property that, given this price process, no risk-averse investor would choose to invest in this asset either long or short.     

Optimal incentives and securitization of defaultable assets

We study optimal securitization in the presence of an initial moral hazard. A financial intermediary creates and then sells to outside investors defaultable assets, whose default risk is determined by the unobservable costly effort exerted by the intermediary. We calculate the optimal contract for any given effort level and show the natural emergence of extreme punishment for defaults, under which investors stop paying the intermediary after the first default. With securitization contracts optimally designed, we find securitization improves the intermediary's screening incentives. Furthermore, the equilibrium effort level and the surplus converge to their first best levels with sufficiently many assets.     

Market Risk of Mortgage-Backed Securities with Consistent Measures

Due to the complex prepayment behavior, mortgage contracts and their derivatives are generally priced using Monte Carlo simulations. The typical approach used by the industry, which involves simulating interest rates under the risk-neutral measure and applying a physically measured prepayment function, is subject to the problem of internal inconsistency. This is the first paper that directly investigates the potential impact of this issue. Following the general equilibrium setting by Cox, Ingersoll and Ross, we incorporate the market risk price parameter to derive the physical interest rate process from an observed yield curve. This allows us to model mortgage values under the consistent physical measures of interest rates and prepayment functions. By analyzing a default-free Ginnie Mae MBS, we find that the mixed measures lead to slower prepayment rate estimates and overpriced mortgage securities by approximately 5%. Further, there can be substantial biases in the duration and convexity measures depending on market condition and the particular security of interest. The internal inconsistency also leads to biased predictions of both expected and stressed returns for different investment horizons. Depending on the particular security, the bias in expected and stressed returns can be either positive or negative. These biases in risk estimates can introduce misallocation of risk-based capital and/or failure in hedging the market risk of a mortgage-related portfolio.

Choosing between fixed-and adjustable-rate mortgages: The case of commercial mortgages

This article reports on the determinants of the ARM choice for commercial real estate projects. The theoretical literature suggests that commercial real estate projects are more likely to be financed with an adjustable-rate mortgage (ARM) if the project's income stream or value is expected to rise with inflation over time. The empirical model estimated is a structural probit probability model of the ARM choice. Our results demonstrate that commercial borrowers typically place great emphasis on relative interest-rate differentials when deciding which mortgage is best. We also find that commercial mortgage borrowers will ordinarily be reluctant to issue an ARM when the fixed interest rate is low.     

Pricing exotic options using MSL-MC

Today, better numerical approximations are required for multi-dimensional SDEs to improve on the poor performance of the standard Monte Carlo pricing method. With this aim in mind, this paper presents a method (MSL-MC) to price exotic options using multi-dimensional SDEs (e.g. stochastic volatility models). Usually, it is the weak convergence property of numerical discretizations that is most important, because, in financial applications, one is mostly concerned with the accurate estimation of expected payoffs. However, in the recently developed Multilevel Monte Carlo path simulation method (ML-MC), the strong convergence property plays a crucial role. We present a modification to the ML-MC algorithm that can be used to achieve better savings. To illustrate these, various examples of exotic options are given using a wide variety of payoffs, stochastic volatility models and the new Multischeme Multilevel Monte Carlo method (MSL-MC). For standard payoffs, both European and Digital options are presented. Examples are also given for complex payoffs, such as combinations of European options (Butterfly Spread, Strip and Strap options). Finally, for path-dependent payoffs, both Asian and Variance Swap options are demonstrated. This research shows how the use of stochastic volatility models and the θ scheme can improve the convergence of the MSL-MC so that the computational cost to achieve an accuracy of O(ε) is reduced from O(ε^?3) to O(ε^?2) for a payoff under global and non-global Lipschitz conditions.     

Auction failures and the market for auction rate securities

The market for auction rate securities (ARS) made headlines during the second week of February 2008 when auctions at which the bonds’ interest rates reset experienced a wave of “failures.” Contrary to headlines that attribute the failures to a “frozen” market or investors’ “irrationality,” we find that (1) even at their height, less than 50% of ARS experienced auction failures, (2) the likelihood of auction failure was directly related to the level of the bonds’ “maximum auction rates,” (3) the implied market clearing yields of bonds with failed auctions were significantly above their maximum auction rates, and (4) ARS yields were generally higher than yields of various cash equivalent investment alternatives. We infer that investors priced the possibility of auctions failures into ARS yields and rationally declined to bid for bonds for which required market yields exceeded their maximum auction rates.     

The valuation and securitization of commercial and multifamily mortgages

This paper develops a pricing model capable of accurately valuing commercial mortgages and their mortgage backed securities (MBS). It is the first example in the general literature on mortgage pricing in which the valuation of an MBS is explicitly tied to that of the underlying mortgages, making possible a comparison of the performance of the loans and the securities they back. We have shown that while there are similarities between mortgages and their mortgage backed securities, they act in different ways. In general, it turns out that despite being the more passive asset, the mortgage backed security exhibits the more complicated behavior.     

Do asset backed securities ratings matter on average?

This paper assesses the impact of asset backed ratings on the Merrill Lynch US Asset Backed Securities and Commercial Mortgage Backed Securities Index (CABs index) over a period January 1998 through to February 2010. In particular, we examine the relationship between ratings changes of the asset backed securities and the CABS index return. We further investigate how macroeconomic variables affect the relation between change in ratings and the CABS index return. We find that on their own, ratings of assets backed securities do matter to the CABS index return. However, controlling for economic factors appears to reduce the impact of the ratings changes on the CABS index return.