Government debt spillovers in a monetary union

This paper presents estimates of the impact of debt issued by one government in a monetary union on the yields of the bonds issued by other governments in the union. These debt spillovers may occur if there is a risk of monetary accommodation, implicit or explicit inter-jurisdictional bailout provisions, or interdependent revenues. The analysis empirically distinguishes between two channels through which debt spillovers may affect bond yields: currency depreciation risk and default risk. Data on the yields of individual Canadian provincial government bonds for the period 1983–2005 are employed. No evidence is found of debt spillovers between provinces, but a one percentage point increase in the central government's debt to GDP ratio raises the yield on provincial government bonds by 4.2 basis points—2.9 basis points by increasing the expected depreciation rate of the Canadian dollar and 1.3 basis points by raising the risk of provincial government default. These results imply that a rise in the Canadian central government debt to GDP ratio from 0.25 to 0.58, equivalent to the rise that occurred between 1983 and 1995, would lead to an increase in provincial government bond yields of approximately 140 basis points.