An early gain for US stocks faded away in the afternoon, leaving indexes slightly lower. The slight losses Monday came after the market closed out its best week of the year. Video game retailer GameStop sank 4% after reporting earnings and revenue that fell short of analysts' forecasts. Pfizer and Allergan fell 3% each after announcing a deal to combine to form the world's biggest drug company. The Dow Jones industrial average fell 31 points, or 0.2%, to 17,792. The Standard & Poor's 500 index gave up two points, or 0.1%, to 2,086. The Nasdaq composite edged down two points, or 0.1%, to 5,102. (More stocks stories.)