Multivariate Hawkes process allowing for common shocks

Although the Hawkes process has been widely applied, their probability properties are difficult to obtain, depending on the model structure. This paper proposes a multivariate Hawkes process, which allows for common jumps from each marginal processes. The probability of this common jump is determined by another independent process, which represents the arrival intensity of external shocks to the system. The infinitesimal generator of the new multivariate jump process is derived. Based on that, moments and the Laplace transform are studied, which further demonstrate the advantages of this model structure.