NASDAQ

NASDAQ is the second-largest US stock exchange, launched in 1971 as the first fully electronic market, with no physical trading floor. It became the natural home for technology companies, and its composite index is now dominated by a small number of mega-cap names.

The NASDAQ-100 (the 100 largest non-financial NASDAQ companies) is heavily weighted toward a handful of giants, so the index can move sharply on a single earnings report from one of its largest constituents in a way a more diversified index would not.