Their combined m-cap is larger than the 2017 gross domestic product (GDP) value of all countries barring America, China and Japan, World Bank data shows.
The share prices of Alphabet, Apple, Microsoft and Amazon have run up between 18 per cent and 57 per cent this year, beating 38 stocks from Nifty 50 and 44 stocks from Nifty Next 50. Facebook is the only laggard, down 0.1 per cent in the year to date, hit by the recent weak guidance and the Cambridge Analytica scandal.
Most of the US tech giants have consistently surpassed revenue growth and profit expectations for several quarters now. Besides being fundamentally tech firms, most of these companies are consumer-oriented. The positive outlook on the US economy also augurs well for these companies.