Global Stock Exchanges.

Byline: S. Kamal Hayder Kazmi

Stocks are holding near record highs, keeping the SandP 500 at its highest valuation since 2002, but the market looked a lot different back then. Around 20 percent of the SandP 500 is now made up of five technology companies - Apple, Google parent Alphabet, Facebook, Microsoft and Amazon. Eighteen years ago, one-fifth of the index was made up of 10 companies as diverse as Walmart, Exxon Mobil and Pfizer.

One top trader says the difference between then and now is staggering. That stock...