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

** U.S. natgas futures NGc1 down 1.9% at $4.49 per million British thermal unit; the contract had closed on Friday at its highest since November 13

** Natgas prices slide on record output and ample amounts of gas in storage despite near-record flows to LNG export plants and forecasts of colder weather and higher demand than previously expected over the next two weeks

** Shares of natgas companies: EQT Corp falls ~1%, Cheniere Energy LNG.N dip 1.7%; Energy Transfer ET.N, Williams Companies WMB.N and CNX Resources CNX.N each down marginally

** NextDecade NEXT.O down 2.6% and New Fortress Energy NFE.O falls 5.9%

** NEXT starts regulatory pre-filing process to add a sixth liquefaction unit and an extra marine berth at its Rio Grande LNG project in Texas, with a full application expected in 2026

** ETFs United States Natural Gas Fund UNG.P down 1.9%, and ProShares Ultra Bloomberg Natural Gas BOIL.P falls 3.9%

(Reporting by Pooja Menon in Bengaluru)

((Pooja.Menon@thomsonreuters.com))