a Third workshop on Nonlinear PDEs and Financial Mathematics
BTU
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V. Myrnyy

Heath-Jarrow-Morton Models with Regime-Switching Volatility

Mikael Elhouar

Abstract
This paper studies Heath-Jarrow-Morton (HJM) type of models with regime-switching stochastic volatility. In this setting the forward rate volatility is allowed to depend on the current forward rate curve as well as on a continuous time Markov chain $y$ with fintely many states. Employing the framework developed by Bjork et al, we find necessary and sufficient conditions on the volatility that guarantee that the forward rate process can be represented by a finite dimensional Markovian state space model. These conditions allow us to investigate regime-switching generalizations of some well-known models such as those by Ho-Lee, Hull-White, and Cox-Ingersoll-Ross.