Asus (styled as ASUS, officially ASUSTeK Computer Inc.) is a Taiwanese multinational computer hardware and electronics company headquartered in Taipei, Taiwan. Its products include motherboards, desktops, laptops, monitors, tablet PCs, servers, video cards and mobile phones. It primarily sells products under its own brand but also produces components for other manufacturers, including Apple, Dell and HP. Asus is the world's fifth-largest PC vendor by 2011 unit sales (after HP, Lenovo, Dell and Acer). Asus appears in BusinessWeek's "InfoTech 100" and "Asia's Top 10 IT Companies" rankings. Wall Street Journal Asia ranks it number one in quality and service, and it ranked first in the IT Hardware category of the 2008 Taiwan Top 10 Global Brands survey with a total brand value of US$1.3 billion. Asus has a primary listing on the Taiwan Stock Exchange (TWSE: 2357) and a secondary listing on the London Stock Exchange (LSE: ASKD). The name Asus originates from Pegasus, the winged horse of Greek mythology. Only the last four letters of the word were used in order to give the name a high position in alphabetical listings.