Recent empirical studies examining the asymmetric effects of monetary shocks on economic activity do not systematically control for the non-monetary sources of fluctuations as well as the endogenous component of monetary policy. The evidence of asymmetry could simply reflect the failure to control for these omitted factors. In this paper, we reconsider the asymmetric effects of monetary shocks in the context of a small open economy using information from the yield curve to measure the stance of domestic monetary policy, while allowing both real and monetary foreign shocks to have asymmetric effects on output. Our principal finding is that while controlling for foreign factors dampens the asymmetry in the effects of exogenous domestic monetary shocks, there is nonetheless strong evidence of asymmetry when the effects of the exogenous and systematic components of the yield spread are considered jointly. We find no evidence of asymmetry in the effects of real factors.