GameStop Corp., the largest video-game specialty retailer, surged as much as 6 percent after an analyst almost doubled his price target, citing demand for new consoles and fewer concerns over used-games sales. GameStop rose 4.4 percent to $39.18 at 1:12 p.m. in New York trading, after reaching $39.77. The stock has gained 56 percent this year, eighth among members of the Standard & Poor's 500 Index.