The FAANG stocks came out of the gate fast in 2017 with an average 18.5% return, led by Apple and Facebook with 24% and 23.5% gains, respectively. During the first quarter, the S&P 500 index was up 6.1% on a total return basis. The group came back to earth a bit in the second quarter, averaging a 5.3% return, still higher than the index's 3.1% gain. July has been strong so far, Netflix in particular is up 23%.
The subset makes up approximately 10% of the market value of the S&P 500. Pension plans hold on average 3% as reported by Bloomberg, but that number excludes exposure via investment managers, which is likely much higher.
The collection of tech, or tech adjacent, stocks has driven index performance in recent years, notably in 2015 when the index finished up only 1.4%, buoyed in large part by these stocks. Netflix and Amazon posted returns of 134% and 118% in 2015, respectively; Apple was the outlier than year as shares were down 4.6%.