By James Regan
SYDNEY, Jan 16 (Reuters) - Copper markets in London and Shanghai eased on Tuesday, reversing an earlier uptrend, as the dollar pulled up from a three-year low.
Earlier in the session, copper prices edged up in London and Shanghai, helped by a weaker U.S. dollar, which strengthened during Asian trading hours.
The dollar's index against a basket of six major currencies stood at 90.626, having pulled up from Monday's three-year low of 90.279.
A weaker greenback makes dollar-denominated commodities cheaper for holders of other currencies, while a stronger dollar has a reverse effect.
Monday's decision by the People's Bank of China (PBOC) to lift the yuan's official midpoint to the greenback to a 1-1/2 year high also supported copper prices.
"The moves by the PBOC to raise the fixing of the yuan against the U.S. dollar helped improve the already positive sentiment in the market," ANZ Bank said.
* LONDON COPPER: Three-month copper on the London Metal Exchange was down 0.9 percent at $7,142.25 a tonne, as of 0723 GMT.
* SHANGHAI COPPER: The most-traded copper contract on the Shanghai Futures Exchange ended 0.6 percent lower at 54,300 yuan ($8,435.61)a tonne.
* RIO TINTO: Rio Tinto stuck to a 2018 production target of 510,000-610,000 tonnes of mined copper and 225,000-265,000 tonnes of refined copper. Aluminium production is targeted at 3.5-3.7 million tonnes. For 2017, aluminium production eased 1 percent and mined copper output fell 9 percent.
* CHINA GDP: China's economic growth is expected to have slowed slightly in the fourth quarter from the previous quarter, a Reuters poll showed, as the government extended a crackdown on debt risks and factory pollution.
* YUAN: China's central bank on Monday lifted its official yuan midpoint to the highest level in more than over 1-1/2 years, to 6.4574 per dollar, reflecting solid spot yuan performance on Friday and broad dollar weakness in overseas markets.
* CME COPPER: CME Group won a bigger slice of the copper market in 2017 from its rivals in London and Shanghai, a Reuters analysis of exchange data showed, a trend that is expected to continue though this year.
* OTHER METALS: The rise in the U.S. dollar led to an across-the-board decline in ShFE base metals, with aluminium showing the most dramatic loss of nearly 3 percent.
Three month LME copper
Most active ShFE copper
Three month LME aluminium
Most active ShFE aluminium
Three month LME zinc
Most active ShFE zinc
Three month LME lead
Most active ShFE lead
Three month LME nickel
Most active ShFE nickel
Three month LME tin
Most active ShFE tin
($1 = 6.4370 Chinese yuan)
Reporting by James Regan, Editing by Joseph Radford and Sherry Jacob-Phillips