This study investigates the extent to which the GDP response to a monetary shock depends on the variation of private debt. This is the marginal contribution of private debt, an effect discussed in the financial accelerator literature. We study the USA, the UK, and Germany in the period 1980 (q1) to 2015 (q4), and compare household debt with corporate debt. Our approach is based on the comparison of one baseline structural VAR with an alternative counterfactual VAR for each country. Our findings indicate that household debt has a significant effect on real output, while corporate debt does not seem to exert a systematic influence.