They're down but not out, at least not yet.The stock market has been on fire this year, but much of that performance can be attributed to a handful of tech giants that have a disproportionate weight of the S&P 500 and are benefiting from the artificial intelligence (AI) boom. Many other stocks have been doing well, but it's not that hard to find those moving in the opposite direction.Pharmaceutical giant Pfizer (PFE 1.12%) and social media platform Snap (SNAP 1.29%) belong to this group: Both have significa ...