The $3 trillion stock club isn't a big list; it's just Nvidia (NVDA 0.72%), Microsoft (MSFT 0.48%), and Apple (AAPL -1.09%). Amazon (AMZN 1.75%) is the fourth-largest company in the world, but it is currently valued at around $2.2 trillion, which showcases how large a gap there is between third and fourth place. Of this $3 trillion trio, is there any worth owning right now? After all, they're already quite large; could they get even bigger? Nvidia may be the world's largest company, but its products aren't ...