Nvidia's shares slump more than 6% amid AI-related concerns and reports of a possible foreign intelligence effort targeting CEO Jensen Huang, pushing its market valuation below Microsoft's $4.03 trillion. Nvidia shares dropped over 6% due to AI outlook uncertainty and a probe into CEO Jensen Huang, while Microsoft surpassed Nvidia as the world's second-most valuable company. Nvidia shares fell more than 6% after Monday’s 4.