By Gerry Shih SAN FRANCISCO (Reuters) – Twitter Inc shares slipped on Monday after some of the five lead underwriters of its initial public offering said the social media firm may not achieve Facebook-like scale and its stock may not rise much higher. In their first research reports since the November IPO, only Deutsche Bank and Goldman Sachs recommended buying the stock. Morgan Stanley and JP Morgan issued the equivalent of hold ratings. Twitter shares dipped 1.3 percent to $41 on Monday.