The interior of an Under Armour store is seen on November 03, 2021 in Houston, Texas. Wall Street is not pleased that Under Armour's founder Kevin Plank is returning as its CEO. Shares of the athletic apparel company plunged about 12% on Thursday after the retailer announced late Wednesday that CEO Stephanie Linnartz would be stepping down after barely a year on the job and Plank would replace her on April 1. Following the announcement, both Williams Trading and Evercore ISI downgraded Under Armour and lowe ...