Debt sustainability in Japan and the case for a fiscal council : rising rates are testing Japan's fiscal framework, with debt dynamics hinging on growth and pointing to the need for adjustment and a fiscal council

Japan combines the highest public debt ratio among advanced economies with a fiscal framework that has struggled to anchor fiscal policy. As monetary policy normalises and interest rates rise, concerns about debt sustainability have intensified. We assess Japan's debt dynamics using stochastic debt sustainability analysis, and examine the institutional foundations of its fiscal framework. We show that debt outcomes are highly sensitive to growth assumptions. Under plausible baseline scenarios, debt does not stabilise without sustained primary surpluses and even optimistic growth assumptions require fiscal adjustment relative to the current structural primary balance. Japan's challenge is institutional as well as economic: weak enforcement of fiscal rules and the absence of independent oversight undermine credibility. Strengthening fiscal institutions, particularly through an independent fiscal council, could support debt stabilisation.