The Standard and Poors 500 Index (The USA’s largest 500 companies) has done exceptionally well.

S&P 500 rose is at about 2,240, an all time high.

The S&P 500® is widely regarded as the best single gauge of large-cap U.S. equities.
Within this index assets comprising approximately US$ 2.2 trillion of this total.
The index includes 500 leading companies and captures approximately 80% coverage of available market capitalisation

http://us.spindices.com/indices/equity/sp-500

The top ten companies in the S&P 500. are:

Apple
Microsoft
Exxon Mobile
Johnson & Johnson
Berkshire Hathaway B
Amazon.com
JP Morgan chase & Co
General Electric
Facebook
Wells Fargo