US rate cuts may help American shoppers but they tilt the pitch for some of the world’s fastest-growing countries. Both China and India resort to hefty foreign exchange intervention to temper currency appreciation, mopping up liquidity with domestic borrowing (sterilisation).

For China, the difference in the interest rate it receives on US Treasuries and the 3.5-odd per cent it pays on short-term bills is marginally less attractive than it was. In India, however, sterilisation bills pay about 7 per cent. That implies a rough annual loss of almost $2bn: modest compared with the revaluation on a $250bn reserves pile, but enough to force a policy rethink?