Nvidia has held the position as the world's biggest company since about a year ago, when it became the first to reach $4 trillion in market value. And on July 17, Apple even slipped ahead of Nvidia to become – at least for part of the trading session – the world's biggest company. As these tech giants vie for the position as the world's biggest company, which is the better buy now? APPLE BRIEFLY OVERTAKES NVIDIA AS WORLD'S MOST VALUABLE COMPANY AMID AI INVESTMENT DOUBTSThe case for NvidiaNvidia stock has soared more than 300% over the past three years amid excitement about its position in the AI market. In the latest quarter, Nvidia announced the upcoming release of its first stand-alone central processing unit (CPU), a move that opens the door to a $200 billion market.