As of September 2016, the top 10 world’s largest companies by market cap were these super-companies:
This list changed a lot in the last 20 years, as some of these companies weren’t around back then. Facebook, for example, was founded in 2004. Google (Alphabet) – in 1998. Tencent – also in 1998.
If we take a look at the list of 10 largest companies in the world in 1998, we will find that just 3 of them, Microsoft, Exxon, and GE, are still among the leaders today (link):
In 1998, I was working at IBM, and it was one of the greatest and most influential companies in the world. In fact, IBM has a great website devoted to its history. This is what happened in 1998. I am pretty sure, at that time, almost nobody noticed the birth of either Google or Tencent. Big mistake.
Finally, if you are curious, this is the list of the largest Asian companies: