** Shares of U.S. natural gas companies fall, tracking a fall in natgas futures NGA/

** U.S. natgas futures NGc1 down 0.8% at $3.38 per million British thermal units, keeping the contract on track for its lowest close since June 26

** The natural gas futures slipped to a one-week low on low cash prices, an increase in output so far this month and higher-than-normal amounts of gas in storage

** Shares of natgas companies down: NextDecade NEXT.O falls 1.7% and Energy Transfer ET.N down marginally

** EQT Corp EQT.N dips 2.1%, Cheniere Energy LNG.N falls 1.4% and Williams Companies WMB.N down 2.7%

** ETFs United States Natural Gas Fund UNG.P and ProShares Ultra Bloomberg Natural Gas BOIL.P down 1.5% and 2.7%, respectively

(Reporting by Sumit Saha in Bengaluru)

((Sumit.Saha@thomsonreuters.com;))