Since the Asian financial crisis of 1997-98, most developing Asian economies have rapidly increased their external surpluses and accumulated foreign reserves to reduce their vulnerability to future shocks. China has amassed over $700bn (£397bn, €586bn). Even the city state of Singapore has $100bn, giving it the region's highest per capita reserves.

Asian surpluses have their main counterpart in the expanding US current account deficit, and economists and policymakers have warned for months that global financial imbalances are becoming unsustainably large.