Fortinet is an American multinational corporation headquartered in Sunnyvale, California. It develops and markets cybersecurity software, appliances and services, such as firewalls, anti-virus, intrusion prevention and endpoint security, among others. It is the fourth-largest network security company by revenue. Fortinet was founded in 2000 by brothers Ken and Michael Xie. It raised about $93 million in funding by 2004 and introduced ten FortiGate appliances. That same year was the beginning of a recurring patent dispute between Fortinet and Trend Micro. The company went public in 2009, raising $156 million through an initial public offering. Throughout the 2000s, Fortinet diversified its product lines, adding products for wireless access points, sandboxing, and messaging security, among others. Fortinet was founded in Sunnyvale, California in 2000 by brothers Ken and Michael Xie. The founders had previously served in executive positions at NetScreen and ServGate respectively. The company was initially named Appligation Inc., then renamed to Appsecure in December 2000 and later renamed to Fortinet, based on the phrase "Fortified Networks". It spent two years in research and development, before introducing its first product in 2002.