In the following video, Fool contributor Matt Thalman discusses why Apple (NASDAQ:AAPL) and Microsoft (NASDAQ:MSFT) became the world's largest companies and why Amazon.com (NASDAQ:AMZN) may one day also hold that title.

Matt also explains why investors shouldn't be focusing their time on figuring out what may become the next largest company in the world. Instead, he says, they should spend their time looking for the best companies in different industries, and then everything else will take care of itself.