* Copper hits highest since Dec. 13 at $5,788.50/oz
* Markets brace for more clues on Trump economic plans
* GRAPHIC-2017 metal returns: http://tmsnrt.rs/2eqHKkL (Updates throughout, adds LONDON dateline)
By Jan Harvey
LONDON, Jan 11 (Reuters) - Copper edged lower on Wednesday ahead of a news conference by U.S. President-elect Donald Trump, having earlier hit a four-week high after upbeat Chinese and global economic data fuelled expectations for firm demand this year.
Three-month copper on the London Metal Exchange was down 0.2 percent at $5,750.50 a tonne at 1035 GMT, off a peak of $5,788.50, its highest since Dec. 13.
The metal surged more than 10 percent in the month following Trump's election to the U.S. presidency on Nov. 8, as his pledge to boost infrastructure spending unleashed a wave of investment in industrial commodities.
It softened into year-end as some investors tempered those expectations, but has since taken support from a wave of positive economic data from around the world.
"The strength that we've seen since November has mainly been on the prospect of increased fiscal spending in the United States," Danske Bank analyst Jens Pedersen said. "But we still need to see more specific plans (from Trump), so today's speech will be interesting for the copper market."
"The underlying story is that manufacturing indicators still look good, which could suggest that the global economy has got off to a good start in 2017," he added. "That is supporting prices also."
Further underpinning the metal are rising concerns over supply disruptions. Workers at Chile's Escondida copper mine - the world's biggest - have already rejected a wage offer from BHP Billiton (LON:BLT), raising the prospect of a strike. stocks retreated and the dollar steadied ahead of Trump's news conference at 1600 GMT. MKTS/GLOB
While his election campaign calls for tax cuts and more infrastructure spending have boosted many assets, including stocks and metal, his protectionist statements and a flurry of tweets have kept many investors from adding to risky positions.
"A number of market participants are likely to have been positioning themselves ahead of the press conference that Donald Trump has announced for today," Commerzbank (DE:CBKG) said in a note. "The market hopes that Trump will paint a clearer picture of his planned economic, trade and foreign policy."
Lead and zinc continued their push higher after the previous session's rally, buoyed by supply concerns. Processing fees for China's zinc smelters reached record lows last month as the supply from mines continued to dwindle.
LME lead CMPB3 was up 0.8 percent at $2,207 a tonne, having rallied nearly 6 percent in the last two sessions. Zinc CMZN3 was 0.5 percent higher at $2,734 a tonne.
LME nickel CMNI3 was 0.3 percent down at $10,585, while aluminium CMAL3 was up 0.1 percent at $1,751.50 a tonne, and tin CMSN3 was 0.1 percent higher at $21,170.
PRICES
Three month LME copper
CMCU3
Most active ShFE copper
SCFcv1
Three month LME aluminium
CMAL3
Most active ShFE aluminium
SAFcv1
Three month LME zinc
CMZN3
Most active ShFE zinc
SZNcv1
Three month LME lead
CMPB3
Most active ShFE lead
SPBcv1
Three month LME nickel
CMNI3
Most active ShFE nickel
SNIcv1
Three month LME tin
CMSN3
Most active ShFE tin
SSNcv1