But Under Armour — whose annual revenue of about $5 billion is about one-seventh of Nike's sales — has managed in recent years to sign such young stars as Curry, golfer Jordan Spieth and baseball's Bryce Harper. All signed initial deals followed by lucrative extensions. Under Armour also has signed Aaron Judge of the New York Yankees and Cody Bellinger of the Los Angeles Dodgers, the top rookie performers this season in Major League Baseball.