** Shares of U.S. AI stocks fall in premarket trade after surging popularity of Chinese discount AI model wobbles investors' faith in the profitability of AI

** Startup DeepSeek rolled out a free assistant it says uses lower-cost chips and less data, sparking worries about profits of rivals and the need for costly tech

** Dominant AI chipmaker Nvidia NVDA.O down 1.7%, AI server maker Super Micro SMCI.O down 8% and Dell DELL.N down 7.8%

** Broadcom AVGO.O down 6.9% while smartphone chipmaker Qualcomm QCOM.O falls 1.8%

** Microsoft MSFT.O down 3.3%, Alphabet GOOGL.O down 3.1%, Meta META.O down 3.8%

** Chipmaker Marvell Technology MRVL.O and Advanced Micro Devices AMD.O fall 6.6% and 3.7%, respectively

** Shares of chip-making equipment companies down; Applied Materials AMAT.O down 5.5%, Lam Research LRCX.O down 5.6% and KLA Corp KLAC.O down 5.5%

** Palantir Technologies PLTR.O falls 5.8%

** Smaller AI stocks C3.ai AI.N down 6.1% and BigBear.ai BBAI.N down 4.4%

** Energy firms, which plan on powering AI data centers, fall: Vistra VST.N and Constellation Energy CEG.O down 8.8% and 7.3%, respectively

** U.S.-listed shares of Arm Holdings ARM.O fall 6.6%, while those of TSMC TSM.N fall 7.3%

(Reporting by Pranav Kashyap in Bengaluru)

((Pranav.Kashyap@thomsonreuters.com; +919886482111;))