Nvidia is facing an unprecedented valuation test as a board inquiry into CEO Jensen Huang exposes the US chipmaker to a rare key-person risk, while investors also weigh the midterm elections’ potential impact on Washington’s chip controls and AI regulation. The company’s shares fluctuated in pre-market trading in the United States, sliding more than 5 per cent, following Huang’s bombshell confirmation over the weekend that he had been unfaithful to his wife and would cooperate with an...