Shanghai copper futures closed moderately higher on Thursday, maintaining its recent upward momentum even after China's State Reserves Bureau announced another impending sale of the red metal.
The bureau said it would hold a fourth, 20,000-tonne copper auction on December 7, and part of an unsuccessful effort so far to drive down global prices, after unloading nearly 50,000 tonnes of the metal through three auctions last month.
"The market is so bullish that few believe the SRB could stop its run," said a Shanghai trader. "Instead, many expect strong funds interest in copper to offset technical over-buying."
Shanghai's most active contract, for February, ended at 37,150 yuan ($4,598) a tonne, up 120 yuan from the close on Wednesday when it jumped 2.7 percent.
Combined trading volume of all domestic contracts fell to 97,630 lots from Wednesday's heavy 160,788 lots as high prices deterred buyers, traders said.
On the London Metal Exchange, benchmark three-month copper was quoted at $4,247 per tonne, inching down from $4,250 at the same time on Wednesday but still near a record high of $4,270 hit on the day.
Shanghai's market was closed at the time. Speculation over a large short position held by the bureau, which is responsible for China's strategic commodity stocks, has helped add more than 8 percent to the value of copper on the LME in November.
Shanghai's spot copper prices rose an average of 125 yuan on Thursday to between 38,550 and 39,200 yuan a tonne. Most Shanghai aluminium futures also ended slightly up on Thursday, with most-active contracts March finishing at 17,690 yuan per tonne, up 60 yuan from Wednesday's close.
Combined aluminium market trading volume fell to 13,968 lots from Wednesday's 18,640-yuan lots.
Benchmark LME aluminium futures were at $2,134 a tonne on Thursday, up from $2,128 when the Shanghai market closed on Wednesday.