Under Armour (UAA) was the worst-performing S&P 500 apparel stock in 2017. It plunged a massive 50% during the year. Some other apparel players had stellar performances that year. PVH (PVH), Gap (GPS), and Michael Kors (KORS) surged 52%, 52%, and 46%, respectively. Sportswear competitors Nike (NKE), Columbia Sportswear (COLM), and Lululemon Athletic (LULU) rose more than 20% that same year.