All the world's 10 most valuable companies, including Alphabet, Apple (AAPL) and Microsoft (MSFT), are based in the U.S., according to a USA TODAY analysis of data from S&P Capital IQ based on the S&P Global 1200 index. Alphabet's rise to No. 1 with a market value Tuesday of $554.8 billion is a historic moment. It becomes just the 12th company to be the most valuable in the Standard & Poor's 500 index since 1929, says Howard Silverblatt.