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This paper deals with a constrained stochastic linear-quadratic (LQ for short) optimal control problem where the control is constrained in a closed cone. The state process is governed by a controlled SDE with random coefficients. Moreover, there is a random jump of the state process. In mathematical finance, the random jump often represents the default of a counter party. Thanks to the Itô-Tanaka formula, optimal control and optimal value can be obtained by solutions of a system of backward stochastic differential equations (BSDEs for short). The solvability of the BSDEs is obtained by solving a recursive system of BSDEs driven by the Brownian motions. The author also applies the result to the mean variance portfolio selection problem in which the stock price can be affected by the default of a counterparty. [ABSTRACT FROM AUTHOR]

The issue of giving an explicit description of the flow of information concerning the time of bankruptcy of a company (or a state) arriving on the market is tackled by defining a bridge process starting from zero and conditioned to be equal to zero when the default occurs. This enables us to collect some empirical facts on the behavior of financial markets: When the bridge process is away from zero, investors can be relatively sure that the default will not happen immediately. However, when the information process is close to zero, market agents should be aware of the risk of an imminent default. In this sense the bridge process leaks information concerning the default before it occurs. The objective of this paper is to provide the basic properties of these processes. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we study a backward stochastic differential equation (BSDE for short) driven by a Brownian motion and a jump martingale in a defaultable setting, with a polynomial growth generator. This kind of BSDE has important applications to the defaultable market. To demonstrate this in a strict way, we first prove the existence, uniqueness and uniform estimate of its solution. Then two examples are given to illustrate its applications to recursive utility and contingent claim hedging. [Copyright &y& Elsevier]

In this paper, we consider the default probabilities caused by a jump or by oscillation under a structural credit risk model with jumps. We study the Laplace transforms of the times of default caused by a jump and by oscillation. We derive integro-differential equations and obtain some closed-form expressions for them. By inverting them, we numerically investigate the contributions of the jump component and the diffusion component to the default under a certain choice of the jump size distribution. [ABSTRACT FROM AUTHOR]