Shares in China plummeted to their lowest level in nearly nine months yesterday on a mixture of worries about weaker profits, the effects of the US economy on the rest of the world and an oversupply of new companies coming to the market.

The Shanghai Composite index, which tracks the larger of China's two exchanges, dropped 5.4 per cent to close at 3,411.93 points, matching levels last witnessed in June when the government raised taxes on share trading.