Share prices in New York fell remorselessly, buffeted by the slump in Hong Kong and elsewhere in Asia.
By 2.45 am (Hong Kong time), the Dow Jones, at 7,471.80, had fallen by 243.61 points, or 3.15 per cent. It was the second time in five days the Hang Seng Index had sent a tremor through world equity markets.
The Hang Seng plunged 646.14 points, or 5.79 per cent, to 10,498.2, as fears over the currency peg refused to subside, despite falling interest rates.
Brokers said the falls in Asian shares - typified by Hong Kong's collapse - had raised fears in equity markets around the world about the possible knock-on effects of a slower regional expansion.
Stocks moved lower in all major European markets, with the London FTSE-100 Index down 129.5 points at 4,840.7 at the close. The Hang Seng London Reference Index moved up 38 points to close at 10,530.
The Hang Seng Index lost 18 per cent last week.