MELBOURNE, Sept 21 (Reuters) - London copper eased on Wednesday from four-week highs as markets waited for key decisions by the Japanese and U.S. central banks.
* Three-month copper on the London Metal Exchange had edged down to $4,776 a tonne by 0040 GMT, paring small gains from the previous session. Prices on Tuesday hit their highest since Aug. 22 at $4,800 a tonne.
* Shanghai Futures Exchange copper climbed 0.4 percent to 37,370 yuan ($5,603) a tonne.
* The U.S. Federal Reserve is expected to leave its benchmark overnight interest rate unchanged following its two-day meeting on Wednesday, according to a Reuters poll of economists.
* The U.S. central bank could again cut its forecasts for how high interest rates will need to go in an economy where output, productivity and inflation are growing at a slower pace than in past decades.
* The Bank of Japan is expected on Wednesday to make negative interest rates the centrepiece of a new policy framework - widely seen as a desperate attempt to show it still has the means to fight chronic stagnation.
* China is set to maintain its economic growth momentum this year, Premier Li Keqiang told an economic forum in New York on Tuesday.
* ShFE lead and zinc were also up more than 1.5 percent in the overnight session.
* The global world refined copper market showed an 83,000-tonne deficit in June, compared with a 69,000-tonne deficit in May, the International Copper Study Group (ICSG) said in its latest monthly bulletin.
* BHP Billiton said it disagreed with Australian tax collectors’ assessment that the miner needed to pay $766 million in back taxes and charges for its Singapore commodities marketing hub.
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* The dollar edged up while world stock indexes were flat on Tuesday. MKTS/GLOB]
The U.S. Federal Open Market Committee to release interest rate decision and communique.
Outcome of BOJ policy meeting.
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 = 6.6700 Chinese yuan renminbi Reporting by Melanie Burton; Editing by Joseph Radford