The Intertemporal Government Budget Constraint and Tests for Bubbles

The methodology for the testing of bubbles in asset prices has recently been applied to testing the sustainability of government debt accumulation. In particular, Hamilton and Flavin (1986) and MacDonald and Speight (1987) use the methodology developed by Flood and Garber (1980) in an attempt to identify a period of bubble financing of the budget deficit for the US and UK respectively. MacDonald and Speight and Trehan and Walsh (1988) also use recently developed cointegration methods in an alternative test of the hypothesis of unsustainable financing. This paper uses the above methods to test for bubble financing of the fiscal deficit for Australia. We develop the method to allow for the effects of income growth on the sustainability of deficits and critically appraise some of the methods used in previous studies and suggest improvements. Our finding is that over the period 1953/54 to 1986/87 there is no evidence of unsustainability of government debt. The analysis suggests that instead, seignorage was used to pay for sustained fiscal deficits, and that the overall level of debt as a ratio of GDP fell over the period as a result of strong GDP growth and inflation.