Ken Xie (Chinese: 谢青; pinyin: Xiè Qīng) is an American billionaire businessman who founded Systems Integration Solutions (SIS), NetScreen, and Fortinet. He is CEO of Fortinet, a cybersecurity firm based in Silicon Valley. Xie was previously the CEO of NetScreen, which was acquired by Juniper Networks for $4 billion in 2004. He built the first ASIC-based firewall/VPN appliance in 1996.