SAN FRANCISCO, OCT 2: Three American entrepreneurs of Indian origin have achieved billionaire status, according to Forbes magazine. In the publication's annual listing of the richest Americans, 6 Indian Americans made it to the list of the top 400 in wealth, which, due to ties and family groupings, actually numbered more than 400 individuals.Rajendra Singh, 45, chairman and chief executive officer of Telecom Ventures, which owns a major stake in Vienna-based Teligent, was the highest-ranked Indian American. He was about halfway down the list with a net worth estimated at $1.1 billion. Teligent, which is publicly-traded, is a high-speed data service company.Singh was followed two places later by Sanjiv Sidhu, co-founder and chief executive of Irving (Texas)-based i2 Technologies. The 42-year-old Sidhu also has a net worth of about $1.1 billion. His company, founded in 1988, makes supply chain management software. The richest Indian American in California and in third place among Indian Americansin the US was Vinod Khosla, partner in the Silicon Valley venture capital firm of Kleiner Perkins Caulfield & Byers. Khosla, 44, was given a $1 billion valuation. Kleiner Perkins has seen its stake in Juniper Networks, which was co-founded by Pradeep Sindhu, shoot up in recent weeks to almost $2 billion. Khosla may, in fact, be already moving much higher on the list.The fourth-ranked Indian American on the list was Naveen Jain, founder and president of InfoSpace.com and a former group vice-president at Microsoft. The Bellevue (Washington)-based Jain, 40, had a net worth of $930 million, another valuation that fluctuates greatly with the rise and fall of his company's stock.Infospace features an online index that supplies horoscopes, classified and other information to more than 1,800 websites. Also on the list were Michael Chowdry, 44, founder of Denver, Colorado-based Atlas Air, with a networth of $675 million, and sound system maker Amar Gopal Bose, 70, with $650 million. Three of the top four placeson the list were Microsoft executives. Bill Gates, Microsoft chairman, saw his networth rise to $85 billion, up from $59 billion a year ago. Gates was twice as wealthy as the second richest American, Microsoft co-founder Paul Allen, who has a networth of $40 billion.