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DUBAI, June 4 (Reuters) - Major Gulf stock markets edged down in early trade on Thursday after oil prices declined and the United States said it was investigating Qatar's winning bid for the 2022 soccer World Cup, but Dubai mortgage firm Amlak Finance surged in heavy trade.

Amlak AMLK.DU was the most traded stock in Dubai and rose 12 percent after surging by its daily 15 percent limit in the previous session.

The stock resumed trading this week after being suspended for nearly six years because of debt problems, missing a broad market rally that followed the 2009 financial crisis. The company completed a debt restructuring deal before returning to the stock market.

Dubai-listed shares in Egypt's Orascom Construction OC.DI climbed 0.8 percent after the company posted a net income of $9.5 million for the first quarter of 2015. The firm provided no comparative figures as it was previously part of another company. ID:nL5N0YQ0OG

Other Dubai stocks were mostly negative and the emirate's index .DFMGI slipped 0.2 percent.

Abu Dhabi's bourse .ADI lost just as much as most stocks there declined.

Oil prices, which often influence investor sentiment in the Gulf, fell almost 3 percent on Wednesday and slipped further in Asian trade on Thursday morning. O/R

Qatar's index .QSI was the weakest in the Gulf and edged down 0.6 percent after a U.S. law enforcement official said overnight that the FBI's investigation of bribery and corruption at FIFA included scrutiny of how soccer's governing body awarded World Cup hosting rights to Russia and Qatar. ID:nL1N0YP2P6

However, the main drag on the Doha index was petrochemicals-to-metals conglomerate Industries Qatar IQCD.QA , whose profits are sensitive to oil prices. IQ fell 1.0 percent.

(Reporting by Olzhas Auyezov; Editing by Andrew Torchia and Sunil Nair) ((olzhas.auyezov@thomsonreuters.com)(+971 56 225 4871)(Reuters Messaging: olzhas.auyezov.thomsonreuters.com@reuters.net))

Keywords: MARKETS STOCKS/MIDEAST