Shanghai copper futures closed down at or near their three percent daily limits on Monday, hit by a spree of profit-taking sparked by talk that China might allow its yuan to appreciate, traders said.
The most active August contract plunged 830 yuan to 25,510 yuan ($3,082) per tonne, just shy of its limit-down level of 25,550 yuan.
"The rumours sparked worries as a strong yuan can lead to a surge in copper imports," said a trader.
"Many long-position holders used market talk as a pretext to take profits after copper prices had recorded heavy gains since October."
Speculation circulated in the market despite repeated official denials that China would allow its yuan to appreciate soon.
In the latest, the official Xinhua news agency re-affirmed on Tuesday that the central People's Bank of China had no plan to raise the yuan's exchange rate.