Copper edged higher on Wednesday in a second day of modest gains, boosted by solid results from the biggest US aluminium producer Alcoa and as investors earmarked New Year cash allocations for the sector.
Optimism about further recovery in the world's biggest metals consumer China ahead of trade data also helped three-month copper on the London Metal Exchange add 0.6 per cent to $8,130 per tonne by 1312 GMT. Copper did not trade in official rings, but was bid at $8,090.
The most-traded April copper contract on the Shanghai Futures Exchange closed barely changed at 58,340 yuan ($9,400) a tonne.
LME copper, which gained 4.3 per cent last year, jumped to the highest levels in more than two months last week after a deal on the US budget deficit, establishing a base above the $8,000 a tonne level after touching lows near $7,500 in November.
Analyst Stephen Briggs at BNP Paribas in London said an uptick in risk appetite supported prices and that New Year investor allocations would likely continue to bolster the sector.
"Generally more long-only money comes in to commodities at the beginning of the year and my sense is that's going to be still trickling in over the next week or two, so I'm biased to the upside."
This was balanced by some modest liquididations linked to the second day of commodity index reweighting, he added.
Morgan Stanley said in a note that the Dow Jones/UBS commodity index was shifting its weight towards precious metals from base metals.
The DJ/UBS aluminium weighting fell to 4.9 per cent from 5.9 per cent and zinc declined to 2.5 per cent from 3.4 per cent.
The market was also capped by worries about budget talks in the United States and an election in Italy.
"Concerns over growth coming out of Europe and also the US is keeping a lid on prices moving higher," said Jonathan Barratt, chief executive of Barratt's Bulletin, a Sydney-based commodity research firm.
Investors would closely eye December trade data from China, the world's biggest consumer of most commodities, due to be released on Thursday.
Growth in China's vast manufacturing sector picked up in December, but copper imports were expected to fall as year-end demand dwindled while local output stayed strong.