Under Armour shares rose 4% in Thursday premarket trading after the company beat earnings expectations and slightly revised up its full-year revenue guidance. The sports apparel and accessories company said it had first-quarter net income of $19 million, or 4 cents per share, up 63% from $12 million, or 3 cents per share, for the same period last year. This year's earnings per share reflect the April 7 Class C stock dividend, which had the same effect as a two-for-one stock split. The FactSet consensus was 2 cents per share.