Aug 26, 2011 NEW YORK (Dow Jones)--Copper futures were flat Friday, under pressure from the view that demand growth in the developed world will remain weak, but supported by speculation that supplies of the metal may be tightening.

The most actively traded contract, for September delivery, recently traded up 0.5 cent, or 0.1%, at $4.084 a pound on the Comex division of the New York Mercantile Exchange.

Futures held larger gains early Friday, but grinded lower toward unchanged after the U.S. government lowered its estimate for second-quarter growth. Gross domestic product rose 1.0% during the quarter, the Commerce Department, lower than the previous estimate for a growth rate of 1.3%.

The revision didn't come as a surprise to market participants, but underscored the concerns that growth in the developed world is slumping. The industrial metal is sensitive to the growth outlook because of its widespread uses in construction and manufacturing.

Futures were expected to show little decisive direction ahead of remarks expected Friday from Federal Reserve Chairman Ben Bernanke at an economic symposium in Jackson Hole, Wyo. Bernanke is scheduled to speak at 10 a.m. EDT.

The speech "will the main market mover," traders with RBC Capital Markets said in a note. "We would speculate that any indication from Bernanke about renewed stimulus measures will be taken as a positive and will see the metals bid into the close."

Some market participants are hoping Bernanke will hint at further support for the struggling U.S. economy, though Fed watchers say the chances of such an announcement are slim.

Copper drew support Friday from the view that supplies of the industrial metal are tightening, market participants said.

Stockpiles of the metal stored in Shanghai Futures Exchange warehouses fell this week by 9,756 metric tons, to 102,258 tons, according to exchange data.

Also lifting sentiment was the potential that further strikes at Freeport-McMoRan Copper & Gold Inc.'s (FCX) massive Grasberg mine could curb output there, analysts said. A strike at the Indonesian mine last month slashed output by 35 million pounds.

The copper market has been lifted for much of the last year by the view that mine supply wouldn't be able to be able to keep up with rising demand.