Shares of Mattel MAT, +2.12% traded higher late on Thursday after The Wall Street Journal reported activist investor Barington Capital had built an undisclosed stake in the company. The stock rose 4.3% to $19.05 in after-hours trading. Shares are down 14% in the last year. On Thursday, the WSJ reported that Barington sent a letter to Mattel Chief Executive Ynon Kreiz telling him the company should pursue strategic alternatives for its Fisher-Price and American Girl businesses. Barington founder James Mit ...