March 30 : As global stock markets tumble over deepening worries about war in the Middle East, Nvidia, the world's most valuable company, finds itself trading at its cheapest price-to-earnings multiple since before ChatGPT kicked off the AI boom. The steep drop in Nvidia's PE suggests the dominant AI chipmaker's shares may be a bargain, but one tied to risks and uncertainty that have shaken investors' confidence in the so-called AI trade that has driven Wall Street higher in recent years.