LONDON, Dec 21 (Reuters) - Copper prices pulled back on Thursday as investors shed some of their bullish positions after the market failed to sustain fresh highs.

Three-month copper on the London Metal Exchange slipped 0.6% to $8,535.50 per metric ton by 1045 GMT after it briefly touched a 4-1/2-month peak on Wednesday, but closed slightly weaker.

"The rejection yesterday is still reverberating in the market today with the failure to gain a foothold above the recent highs," said Ole Hansen, head of commodity strategy at Saxo Bank in Copenhagen.

"It's setting up a interesting start to next year because we've been in an uptrend since October and the question is whether it can be maintained."

LME copper has gained about 9% since hitting an 11-month low of $7,856 on Oct. 23.

"The market is most certainly looking for additional support from China next year and also for the green transition to gain momentum," Hansen added.

LME zinc was the biggest decliner on the exchange, dropping 1.2% to $2,543 a ton on worries about oversupply after more arrivals of metal into LME warehouses brought the total to the highest levels since September 2021.

LME nickel was little changed at $16,855 a ton while the most-traded January nickel contract on the Shanghai Futures Exchange dropped 1.3% to 129,830 yuan ($18,169.22) a ton.

On a year-to-date basis, LME nickel is down 44% and SHFE nickel has dropped 35%, making the metal the worst performer across the nonferrous metals complex on the two bourses.

"Nickel supply continues to grow, but consumption has not improved. The surplus pattern continues, and nickel supply and demand are bearish," said Huatai Futures in a report.

China's nickel pig iron prices also dropped to 907.50 yuan a ton by Dec. 19, down 33% from a year earlier.

LME aluminium shed 0.7% to $2,226.50, lead fell 0.6% to $2,071 and tin eased 0.5% to $25,080.

For the top stories in metals click ($1 = 7.1456 yuan) (Reporting by Eric Onstad Additional reporting by Mai Nguyen in Hanoi Editing by Tomasz Janowski)