Shares in Twitter Inc have been found eligible for investment by Islamic funds, according to IdealRatings, a company that screens stocks to determine whether they meet Muslim principles. IdealRatings said it had vetted Twitter in response to requests from fund managers and individual investors around the world. The social media companys share price soared in last weeks New York Stock Exchange debut after a $1.8 billion initial public offer. Islamic fund managers follow guidelines such as bans on investment in firms involved with tobacco, alcohol and gambling.