The Nasdaq Composite gained 20% through August, but is down 9% since. Facebook, Amazon, Apple and Alphabet are down on average 18% over the last three months, according to Yahoo Finance data. Blame slowing user growth at the likes of Facebook or more competition for Amazon from the increasingly digitally savvy Target. Sales for Facebook, Apple, Amazon and Alphabet are expected to grow 17% in 2019 according to Jefferies, cooling from a blistering 26% pace this year. That deceleration in growth is indeed something many investors in big tech are not used to.