Zhou Hongyi, Board Chairman of Qihoo 360 Technology Co. Ltd., became billionaire overnight as his company listed on the New York Stock Exchange on March 30.

Qihoo 360 is a leading provider of Internet and mobile security products in China. The company is famous for its free anti-virus software.

Zhou, 41, was born in Hunan Province and graduated with a master's degree in systems engineering from Xi'an Jiaotong University in 1995. In 1998, he founded 3721 Internet Software Co.

Zhou became the regional director of Yahoo! China in 2003 when 3721 was acquired by Yahoo! In August 2006, Zhou founded Qihoo 360 and became its board chairman.