Default Intensity Processes Research Articles

Valuation of vulnerable European options with market liquidity risk

AbstractIn this paper, we investigate the pricing of vulnerable European options in a market where the underlying stocks are not perfectly liquid. A liquidity discount factor is used to model the effect of liquidity risk in the market, and the default risk of the option issuer is incorporated into the model using a reduced-form model, where the default intensity process is correlated with the liquidity risk. We obtain a semiclosed-form pricing formula of vulnerable options through the inverse Fourier transform. Finally, we illustrate the effects of default risk and liquidity risk on option prices numerically.

Pricing catastrophe equity puts with counterparty risks under Markov-modulated, default-intensity processes

According to the observation of the catastrophic events with regime-switching phenomena and default rate varying with economic condition, we extend the results of Chang et al. (2011) and also take the default rate varying with economic condition into consideration by using the Markov-modulated reduced-form model. In order to value options under stochastic interest rates and a default intensity environment, we employ Girsanov’s theorem to obtain two different forward measures and to derive a pricing formula. We also conduct numerical analyses using Monte Carlo simulations to illustrate the influence of the recovery rate, the time to maturity, the frequency of catastrophic events, and the effect of counterparties’ default intensity on the catastrophe equity put price.

CVA AND VULNERABLE OPTIONS IN STOCHASTIC VOLATILITY MODELS

This work aims to provide an efficient method to evaluate the Credit Value Adjustment (CVA) for a vulnerable European option, which is an option subject to some default event concerning the issuer solvability. Financial options traded in OTC markets are of this type. In particular, we compute the CVA in some popular stochastic volatility models such as SABR, Hull et al., which have proven to fit quite well market derivatives prices, admitting correlation with the default event. This choice covers the relevant case of Wrong Way Risk (WWR) when a credit deterioration determines an increase in the claim value. Contrary to the structural modeling adopted in [G. Wang, X. Wang & K. Zhu (2017) Pricing vulnerable options with stochastic volatility, Physica A 485, 91–103; C. Ma, S. Yue & Y. Ma (2020) Pricing vulnerable options with Stochastic volatility and Stochastic interest rate, Computational Economics 56, 391–429], we use the reduced-form intensity-based approach to provide an explicit representation formula for the vulnerable option price and related CVA. Later, we specialize the evaluation formula and construct its approximation for the three models mentioned above. Assuming a CIR model for the default intensity process, we run a numerical study to test our approximation, comparing it with Monte Carlo simulations. The results show that for moderate values of the correlation and maturities not exceeding one year, the approximation is very satisfactory as of accuracy and computational time.

Basket Credit Derivative Pricing in a Markov Chain Model with Interacting Intensities

In this paper, we propose a Markov chain model to price basket credit default swap (BCDS) and basket credit-linked note (BCLN) with counterparty and contagion risks. Suppose that the default intensity processes of reference entities and the counterparty are driven by a common external shock as well as defaults of other names in the contracts. The stochastic intensity of the external shock is a Cox process with jumps. We derive recursive formulas for the joint distribution of default times and obtain closed-form premium rates for BCDS and BCLN. Numerical experiments are performed to show how the correlated default risks may affect the premium rates.

DEFAULTABLE CLAIMS IN SWITCHING MODELS WITH PARTIAL INFORMATION

We study a credit risk model for a financial market in which the local drift rate of the logarithm of the intensity of the default time changes at the times at which certain unobservable external events occur. The risk-neutral dynamics of the default intensity are described by a generalized geometric Brownian motion and the changes of the local drift rate arrive at independent exponential times. We obtain closed form expressions for the rational values of defaultable European-style contingent claims through the filtering estimates of the occurrence of switching times given the filtration generated by the default intensity process.

Valuation of European option with correlated credit risk and stochastic interest

In this paper, we derive an explicit pricing formula for vulnerable call options where the credit risk is handled in a hybrid model. We describe the process of default via a doubly stochastic Poisson process, and assume that the intensity process λ of the Poisson process follows a mean-reverting process. Moreover, the default intensity process λ mutually correlates with the underlying asset and the value of the firm. By applying a changing measure, closed-form solutions of the pricing formula are derived within a general Gaussian interest rate framework.

Pricing catastrophe options with counterparty credit risk in a reduced form model

In this paper, we study the price of catastrophe options with counterparty credit risk in a reduced form model. We assume that the loss process is generated by a doubly stochastic Poisson process, the share price process is modeled through a jump-diffusion process which is correlated to the loss process, the interest rate process and the default intensity process are modeled through the Vasicek model. We derive the closed form formulae for pricing catastrophe options in a reduced form model. Furthermore, we make some numerical analysis on the explicit formulae.

Rational multi-curve models with counterparty-risk valuation adjustments

We develop a multi-curve term structure set-up in which the modelling ingredients are expressed by rational functionals of Markov processes. We calibrate to London Interbank Offer Rate swaptions data and show that a rational two-factor log-normal multi-curve model is sufficient to match market data with accuracy. We elucidate the relationship between the models developed and calibrated under a risk-neutral measure and their consistent equivalence class under the real-world probability measure . The consistent -pricing models are applied to compute the risk exposures which may be required to comply with regulatory obligations. In order to compute counterparty-risk valuation adjustments, such as credit valuation adjustment, we show how default intensity processes with rational form can be derived. We flesh out our study by applying the results to a basis swap contract.

Real-Time Risk Management: An AAD-PDE Approach

We apply adjoint algorithmic differentiation (AAD) to the risk management of derivative securities in the situation where the dynamics of securities prices are given in terms of partial differential equations (PDE). With simple examples, we show how AAD can be applied to both forward and backward PDEs in a straightforward manner. In particular, in the context of one-factor short-rate models for interest rates or default intensity processes, we show how one can compute price sensitivities reliably and orders of magnitude faster than with a standard finite-difference approach. This significantly increased efficiency is obtained by combining (i) the adjoint of a forward PDE for calibrating the parameters of the model, (ii) the adjoint of a backward PDE for pricing the derivative security, and (iii) the implicit function theorem to avoid iterating the calibration procedure.

Investigating the Performance of Non-Gaussian Stochastic Intensity Models in the Calibration of Credit Default Swap Spreads

Most important financial models assume randomness is explained through a normal random variable because, in general, use of alternative models is obstructed by the difficulty of calibrating and simulating them. Here we empirically study credit default swap pricing models under a reduced-form framework assuming different dynamics for the default intensity process. We explore pricing performance and parameter stability during the highly volatile period from June 30, 2008 to December 31, 2010 for different classes of processes driven by Brownian motion, three non-Gaussian Levy processes, and a Sato process. The models are analyzed from both a static and dynamic perspective.

A collateralized loan’s loss under a quadratic Gaussian default intensity process

In this study, we derive an analytical solution for the expected loss and the higher moment of the discounted loss distribution for a collateralized loan. To ensure non-negative values for the intensity and interest rate, we assume a quadratic Gaussian process for the default intensity and discount interest rate. Correlations among default intensity, discount interest rate, and collateral value are represented by correlations among Brownian motions driving the movement of the Gaussian state variables. Given these assumptions, the expected loss or the th moment of the loss distribution is obtained by a time integral of an exponential quadratic form of the state variables. The coefficients of the form are derived by solving ordinary differential equations. In particular, with no correlation between the default intensity and the discount interest rate, the coefficients have explicit closed-form solutions. We use numerical examples to analyse the effects of the correlation between the default intensity and the collateral value on expected loss and the standard deviation of the loss distribution.

An Empirical Comparison of Alternative Credit Default Swap Pricing Models

Most of the important models in finance rest on the assumption that randomness is explained through a normal random variable because, in general, the use of alternative models is obstructed by the difficulty of calibrating and simulating them. In this paper, we empirically study models for pricing credit default swaps under a reduced-form framework, assuming different dynamics for the default intensity process. After reviewing the most recent results on this subject, we explore both pricing performance and parameter stability during the highly volatile period from 30 June 2008 to 31 December 2010 for different classes of processes: one driven by the Brownian motion, three driven by non-Gaussian Levy processes, and the last one driven by a Sato process. The models are analysed from both a static and dynamic perspective.

On a reduced form credit risk model with common shock and regime switching

Reduced form credit risk models are important ones in credit risk theory. In such a model, certain correlated relations are constructed to represent the default dependence structure among the default intensity processes. In this paper, we introduced a reduced form credit risk model in which the default dependence structures among default intensity processes are described by the so-called common shocks with regime-switching. We derive some closed-form expressions for the joint distribution of the default times and for the pricing formulas of the basket default swaps. We also give numerical results to show the applicable aspects of the proposed model.

Pricing for Basket CDS and LCDS

In this paper, under the reduced form framework and “Bottom Up” method, a model for pricing a basket Loan-only Credit Default Swap (LCDS), with the negative correlation between prepayment and default, is established. A general pricing formula for it is obtained, where one factor CIR (Cox-Ingersoll-Ross) and ICIR (Inversed CIR) models are used to describe the negative correlation between prepayment and default. In this situation, the positivity of prepayment and default intensity processes are guaranteed. Numerical computations are presented.

COUNTERPARTY RISK FOR CREDIT DEFAULT SWAP WITH STATES RELATED DEFAULT INTENSITY PROCESSES

In this paper, the counterparty risk is considered in pricing a Credit Default Swap (abbr. CDS). We adopt an intensity-based reduced form model, in which the default intensity processes of the counterpart and the reference credit are modulated by the credit states of the firms. Two Markov chains are used to describe the credit state processes. We set up a model where the default correlation between the counterpart and the reference is described through the Markov chains. A semi-explicit formula for the pricing of CDS with counterparty risk is obtained. We analyze the impacts of default correlations and the state changes on the CDS price through some numerical experiments.

RECOVERING PORTFOLIO DEFAULT INTENSITIES IMPLIED BY CDO QUOTES

We propose a stable nonparametric algorithm for the calibration of “top‐down” pricing models for portfolio credit derivatives: given a set of observations of market spreads for collateralized debt obligation (CDO) tranches, we construct a risk‐neutral default intensity process for the portfolio underlying the CDO which matches these observations, by looking for the risk‐neutral loss process “closest” to a prior loss process, verifying the calibration constraints. We formalize the problem in terms of minimization of relative entropy with respect to the prior under calibration constraints and use convex duality methods to solve the problem: the dual problem is shown to be an intensity control problem, characterized in terms of a Hamilton–Jacobi system of differential equations, for which we present an analytical solution. Given a set of observed CDO tranche spreads, our method allows to construct a default intensity process which leads to tranche spreads consistent with the observations. We illustrate our method on ITRAXX index data: our results reveal strong evidence for the dependence of loss transitions rates on the previous number of defaults, and offer quantitative evidence for contagion effects in the (risk‐neutral) loss process.

A lattice approach for pricing convertible bond asset swaps with market risk and counterparty risk

This paper proposes a new lattice framework for valuing convertible bonds (CBs) and asset swaps on CBs (CBASs) with market risk and counterparty risk, where interest rate is assumed to follow a mean-reverting square root process. The reduced-form approach is generalized to include a constant elasticity of variance (CEV) process for equity price prior to default. In order to approximate the CEV process while taking into account stochastic interest rate and the correlation between stock price and interest rate, I first propose a transform that is uncorrelated with interest rate, and then construct a new lattice method which can ensure the validity of branching probabilities for all nodes. The lattice framework performs properly when it is used to value European call options. Based on the empirical results in Duffie et al. (J. Fin. Econ. 83(3): 635–665, 2007) and Jankowitsch et al. (J. Bank. Fin. 32(7): 1269–1285, 2008), a novel default intensity process is constructed which is specified as a function of time, stock price, and interest rate. When valuing the asset swaps, the counterparty risk is taken into consideration. Based on the results of the numerical experiments, the impacts of different parameters on the prices of CBs and CBASs are explained.

Economic determinants of default risks and their impacts on credit derivative pricing

AbstractThis study constructs a credit derivative pricing model using economic fundamentals to evaluate CDX indices and quantify the relationship between credit conditions and the economic environment. Instead of selecting specific economic variables, numerous economic and financial variables have been condensed into a few explanatory factors to summarize the noisy economic system. The impacts on default intensity processes are then examined based on no‐arbitrage pricing constraints. The approximated results show that economic factors indicated credit problems even before the recent subprime mortgage crisis, and economic fundamentals strongly influenced credit conditions. Testing of out‐of‐sample data shows that credit evolution can be identified by dynamic explanatory factors. Consequently, the factor‐based pricing model can either facilitate the evaluation of default probabilities or manage default risks more effectively by quantifying the relationship between economic environment and credit conditions. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark

Valuation of Portfolio Credit Derivatives with Default Intensities Using the Vasicek Model

We present a methodology for valuing portfolio credit derivatives under a reduced form model for which the default intensity processes of risk assets follow the one-factor Vasicek model. A closed-form solution of joint survival time distribution is obtained. The solution is applied to value credit derivatives of a credit default swap index and collateralized debt obligation. The limitation of methods using the Vasicek model is discussed. We propose that the method is valid and efficient for a portfolio with small-scale correlated risk assets, for which the acceptable size is much greater than for the traditional method. Numerical examples and parameter analysis are also presented.

Liquidity spreads in the corporate bondmarket: Estimation using a semi-parametric model

This study utilizes the liquidity risk associated with Treasury bonds to directly determine the degree to which liquidity spreads account for corporate bond spreads. This enhances understanding of their relative contributions to the yield spreads of corporate bonds. To capture time variation on instantaneous spreads and volatility and to reduce modeling bias, semi-parametric techniques are applied to estimate the time-varying intensity process. Empirical results indicate that our semi-parametric model is good at capturing the time variation in default and liquidity intensity processes. The credit spreads are due to default risk and reflect the relative liquidity of the corporate bond market, indicating that liquidity risk plays an important role in corporate bond valuation.