This paper proposes a multivariate unobserved components model to simultaneously decompose the real GDP for each of the G 7 countries into their respective trend and cycle components. In contrast to previous literature, our model allows for explicit correlation between all the contemporaneous trend and cycle shocks. This approach thus allows us to distinguish cross country correlation driven by shared trend shocks from correlation between the cycle shocks.We find that fluctuations in output are primarily due to permanent shocks for all of the G 7 countries. We also find that common restrictions on the correlations between trend and cycle shocks are rejected by the data. With regards to cross country relationships, we find some countries share more transitory shocks, such as Canada and the US, whereas others, such as Germany and France, share more permanent shocks.