Chinese state media reported on Thursday that Beijing would release copper stocks from its reserves to help lower prices, confirming widespread industry expectations that the State Reserves Bureau would intervene in the market.
"It got marked down on the back of it, but volumes have been very thin," a Hong Kong-based trader said by phone.
The report didn't specify the volume of reserves to be released or the timetable.
Industry officials have estimated that the reserves bureau could release up to 80,000 tonnes of its roughly 200,000 tonnes of reserves to try to push down the high price of benchmark London copper futures.
But traders played down the impact of the move saying the lack of volume had increased volatility and suggested the dip in prices could spur buying when London trade begins later in the day.
"Because the market is so illiquid, when somebody trades it doesn't take much to push the market around $40 or $50."
Key London Metal Exchange (LME) copper for delivery in three months was at $3,930/$3,936 by 0412 GMT, down from $3,943 at the close on Wednesday and below a record hit last month of $4,018 a tonne.
Trade was quietened with the Culture Day holiday in Japan, and the Eid-ul-Fitr celebration closed markets in Singapore, Indonesia and Malaysia.
Liquidity is also low due to the LME annual conference this week, making dealers reluctant to take new positions.
A Singapore trading house saw resistance at $3,955/$3,960.
Copper futures on the Shanghai Futures Exchange rose across the board despite the news about the Chinese reserves, with the most active December contract adding 80 yuan to trade at 36,730 yuan per tonne.
In other metals, aluminium was at $1,988/$1,993 per tonne, down from $2,000 at London's close, while zinc $1,541/$1,548 a tonne, steady with the previous close.
Nickel was at $11,600/$11,700 against $11,670 and tin was untraded at $6,200/$6,300 as was lead at $940/$945.