Saudi billionaire Prince Alwaleed Bin Talal has raised his stake in social networking site Twitter, making him the second-largest shareholder in the company. He and his investment company Kingdom Holding Co. hold 34.9 million shares in common stock, increasing the stake to 5.2%, a disclosure with the Securities and Exchange Commission revealed. This comes as Twitter appointed co-founder Jack Dorsey as CEO this week in a bid to invigorate the company. Prince Alwaleed now holds 30.1 million shares and Kingdom Holding, 4.85 million. He invested $300 million (AED1.1 billion) in the site in 2011, before its initial public offering in November 2013, according to the statement.