This is the special lesson Warren Buffett gave new stock investors at his annual meeting

This is the special lesson Warren Buffett gave new stock investors at his annual meeting

Warren Buffett took a special moment at the start of Berkshire Hathaway's annual shareholders' meeting Saturday to speak to the record amount of new investors rushing into markets.

The lesson was about the uncertainty around individual stocks, comparing the top 20 stocks in the world by market value as of March 31 of this year and comparing it to a similar list from 1989, which had many companies from Japan, a country with a hot stock market at the time, along with some U.S. companies.

The top companies in 1989 included Industrial Bank of Japan, worth $104 billion, Sumitomo Bank, Exxon, General Electric and IBM. The list today includes Apple, Saudi Aramco, Microsoft and Amazon.

The billionaire noted the value of the top companies in the world (Apple worth more than $2 trillion) has increased significantly, but importantly there was not a single company on the list today that was there in 1989.

"We were just as sure of ourselves, and Wall Street was, in 1989 as we are today. But the world can change in very, very dramatic ways," said Buffett.

While the tremendous increase in value of the top global companies (now worth trillions instead of billions) tells you some things about