CGMY and Meixner Subordinators are Absolutely Continuous with respect to One Sided Stable Subordinators

We describe the CGMY and Meixner processes as time changed Brownian motions. The CGMY uses a time change absolutely continuous with respect to the one-sided stable $(Y/2)$ subordinator while the Meixner time change is absolutely continuous with respect to the one sided stable $(1/2)$ subordinator$.$ The required time changes may be generated by simulating the requisite one-sided stable subordinator and throwing away some of the jumps as described in Rosinski (2001)

OPTION PRICING WITH V. G. MARTINGALE COMPONENTS

European call options are priced when the uncertainty driving the stock price follows the V. G. stochastic process (Madan and Seneta 1990). The incomplete markets equilibrium change of measure is approximated and identified using the log return mean, variance, and kurtosis. An exact equilibrium interpretation is also provided, allowing inference about relative risk aversion coefficients from option prices. Relative to Black-Scholes, V. G. option values are higher, particularly so for out of the money options with long maturity on stocks with high means. low variances, and high kurtosis.Option, pricing, Variance Gamma, martingale

CONTINGENT CLAIMS VALUED AND HEDGED BY PRICING AND INVESTING IN A BASIS

Contingent claims with payoffs depending on finitely many asset prices are modeled as elements of a separable Hilbert space. Under fairly general conditions, including market completeness, it is shown that one may change measure to a reference measure under which asset prices are Gaussian and for which the family of Hermite polynomials serves as an orthonormal basis. Basis pricing synthesizes claim valuation and basis investment provides static hedging opportunities. For claims written as functions of a single asset price we infer from observed option prices the implicit prices of basis elements and use these to construct the implied equivalent martingale measure density with respect to the reference measure, which in this case is the Black-Scholes geometric Brownian motion model. Data on S&P 500 options from the Wall Street Journal are used to illustrate the calculations involved. On this illustrative data set the equivalent martingale measure deviates from the Black-Scholes model by relatively discounting the larger price movements with a compensating premia placed on the smaller movements.Contingent claims, options, Hilbert space, Hermite, S & P 500 index

Pricing the Risks of Default

This paper characterizes the risk neutral jump process of default in terms of two entities, i) an instantaneous arrival rate of default and ii) a conditional density of the magnitude of the proportionate reduction in the value of creditors claims. The authors propose models for default arrival and magnitude risks as functions of evolving economic information. These two default components are then explicitly priced in the futures market with the spot price of risky debt being derived as a consequence. The resulting models for default arrival and magnitude risks are estimated on monthly data for rates on certificates of deposit offered by institutions in the Savings and Loan Industry. The data period is January 1987 to December 1991. The default arrival rate is modeled as responsive to abnormal equity returns, while default magnitude risk is modeled to be sensitive to the level of core deposits and the yield on low grade bonds. The authors' empirical results for the arrival and magnitude risk models provide strong support for the hypothesis that uninsured depositors place market discipline on the depository institutions by demanding compensation for both forms of the firm's default risks.

A Two-Factor Hazard-Rate Model for Pricing Risky Debt and the Term Structure of Credit Spreads

This paper proposes a two-factor hazard-rate model, in closed-form, to price risky debt. The likelihood of default is captured by the firm's non-interest sensitive assets and default-free interest rates. The distinguishing features of the model are threefold. First, impact of capital structure changes on credit spreads can be analyzed. Second, the model allows stochastic interest rates to impact current asset values as well as their evolution. Finally, the proposed model is in closed form enabling us to undertake comparative statics analysis, compute parameter deltas of the model, calibrate empirical credit spreads and determine hedge positions. Credit spreads generated by our model are consistent with empirical observations.

CAPM, rewards, and empirical asset pricing with coherent risk

The paper has 2 main goals: 1. We propose a variant of the CAPM based on coherent risk. 2. In addition to the real-world measure and the risk-neutral measure, we propose the third one: the extreme measure. The introduction of this measure provides a powerful tool for investigating the relation between the first two measures. In particular, this gives us - a new way of measuring reward; - a new approach to the empirical asset pricing

Pricing and hedging in incomplete markets with coherent risk

We propose a pricing technique based on coherent risk measures, which enables one to get finer price intervals than in the No Good Deals pricing. The main idea consists in splitting a liability into several parts and selling these parts to different agents. The technique is closely connected with the convolution of coherent risk measures and equilibrium considerations. Furthermore, we propose a way to apply the above technique to the coherent estimation of the Greeks

Coherent measurement of factor risks

We propose a new procedure for the risk measurement of large portfolios. It employs the following objects as the building blocks: - coherent risk measures introduced by Artzner, Delbaen, Eber, and Heath; - factor risk measures introduced in this paper, which assess the risks driven by particular factors like the price of oil, S&P500 index, or the credit spread; - risk contributions and factor risk contributions, which provide a coherent alternative to the sensitivity coefficients. We also propose two particular classes of coherent risk measures called Alpha V@R and Beta V@R, for which all the objects described above admit an extremely simple empirical estimation procedure. This procedure uses no model assumptions on the structure of the price evolution. Moreover, we consider the problem of the risk management on a firm's level. It is shown that if the risk limits are imposed on the risk contributions of the desks to the overall risk of the firm (rather than on their outstanding risks) and the desks are allowed to trade these limits within a firm, then the desks automatically find the globally optimal portfolio

On dynamic spectral risk measures, a limit theorem and optimal portfolio allocation

In this paper we propose the notion of continuous-time dynamic spectral risk-measure (DSR). Adopting a Poisson random measure setting, we define this class of dynamic coherent risk-measures in terms of certain backward stochastic differential equations. By establishing a functional limit theorem, we show that DSRs may be considered to be (strongly) time-consistent continuous-time extensions of iterated spectral risk-measures, which are obtained by iterating a given spectral risk-measure (such as Expected Shortfall) along a given time-grid. Specifically, we demonstrate that any DSR arises in the limit of a sequence of such iterated spectral risk-measures driven by lattice-random walks, under suitable scaling and vanishing time- and spatial-mesh sizes. To illustrate its use in financial optimisation problems, we analyse a dynamic portfolio optimisation problem under a DSR.Comment: To appear in Finance and Stochastic

The Multinomial Option Pricing Model and Its Brownian and Poisson Limits

The Cox, Ross, and Rubinstein binomial model is generalized to the multinomial case. Limits are investigated and shown to yield the Black-Scholes formula in the case of continuous sample paths for a wide variety of complete market structures. In the discontinuous case a Merton-type formula is shown to result, provided jump probabilities are replaced by their corresponding Arrow-Debreu prices.Multinomial, option, pricing, Brownian, Poisson