* FTSEurofirst 300 loses 0.2 pct, down 1.1 pct on the week
* EADS sinks on A350 delivery concerns
* Commerzbank hit by capital increase concerns
* For up-to-the-minute market news, click on
By Blaise Robinson
PARIS, Aug 27 (Reuters) - European stocks were down around midday on Friday, reversing the previous day's tentative rebound and resuming their week-long losing run, as investors braced for a weak U.S. GDP figure following a raft of grim economic data.
The revised GDP data for the second quarter is expected to confirm the slowing pace of the economic recovery, in the wake of this week's bleak housing data.
Investors were also awaiting comments from Federal Reserve Chairman Ben Bernanke, who will delivers a speech that is expected to give insight on whether the Fed will support the struggling economy with fresh injections of cash.
At 1022 GMT, the FTSEurofirst 300 index of top European shares was down 0.2 percent at 1,018.12 points, on track to post a loss of 1.1 percent on the week, the index's third straight week of losses.
The Euro STOXX 50, the euro zone's blue chip index, was down 0.3 percent at 2,599.82 points, after falling to as low as 2,585.50 points earlier, a hair above a key support level, the 23.6 percent Fibonacci retracement of the index's fall from an April high to a May low.
"The market has been overreacting to the flow of sluggish data. The U.S. economic recovery is grinding to a halt but it doesn't mean it will slip back into recession," said Francois Chevallier, strategist at Banque Leonardo, in Paris.
"What has been priced in is the gloomiest scenario, but it won't happen."
Airbus parent EADS dropped 4.4 percent, trimming this year's sharp gains, after Les Echos newspaper reported Airbus told its suppliers it will reduce the number of A350 wide-body airplanes it will produce in 2013, 2014, and 2015.
Commerzbank fell 2.5 percent after German business daily Handelsblatt cited financial sources as saying the company was planning a capital increase of at least 5 billion euros this fall.
Banking stocks were under pressure, with Barclays, Societe Generale and UniCredit down 0.7-1.3 percent.
Shares of resource-related shares also lost ground, with BP down 1.9 percent and Anglo American down 1.4 percent.
Tullow Oil fell 4.3 percent after reports in the Ugandan press that the government was refusing to extend one of Tullow's oil licenses.
The recent market pull-back has dragged European stock valuations to near two-month lows. Shares in the FTSEurofirst 300 trade at an average 12.2 times reported earnings.
The U.S. Commerce Department is due to release its second estimate of Q2 GDP growth at 1230 GMT. Economists in a Reuters survey forecast a 1.4 percent annualized rate of growth compared with a 2.4 percent rate in the first estimate.
"We need to have some clear evidence for the U.S. economy to turn the corner to get people to look at the equity market again," said Franz Wenzel, strategist at AXA Investment Managers in Paris. (Additional reporting by Atul Prakash, Editing by Mark Potter)