SEOUL/SYDNEY — Nvidia shares declined on Monday after an internal investigation into whether CEO Jensen Huang had been targeted by a foreign intelligence effort put his future at the AI chipmaker under scrutiny. The internal probe followed a media report that Huang had a close relationship with a Chinese businesswoman who allegedly passed information to Beijing. Huang told Nvidia's employees that he had been unfaithful to his wife, without disclosing details of the relationship. The investigation, announced on Sunday, has put a spotlight on 63-year-old Huang's future given Nvidia's status as the world's most valuable chipmaker and the CEO's role as the most prolific salesman of the AI boom. The leather-jacketed Huang enjoys rock-star status worldwide, particularly in Asia, where he often mingles freely with fans, taking selfies and signing autographs for his devoted followers. He is Nvidia's fifth-largest shareholder with a roughly 3.6 percent stake, according to LSEG data, and keeps a tight grip on the company through an unusually flat structure in which dozens of executives report di