In this note, I consider a general class of unobserved components (UC) models and derive a relevant inequality. This inequality implies that either of the two assumptions of standard UC models, namely, a random walk trend and uncorrelated shocks, is not satisfied if the impulse response measure...

This paper proposes a couple of new methods to compute the news impact curve for stochastic volatility (SV) models. The new methods incorporate the joint movement of return and volatility, which has been ignored by the extant literature. The first method employs the Bayesian Markov chain Monte...