High Quality Content by WIKIPEDIA articles! ARM Holdings plc (LSE: ARM, NASDAQ: ARMH) is a British multinational semiconductor and software company headquartered in Cambridge. Its largest business is in processors, although it also designs, licenses and sells software development tools under the RealView and KEIL brands, systems and platforms, system-on-a-chip infrastructure and software. It is considered to be market dominant in the field of mobile phone chips and is arguably the best-known of the `Silicon Fen` companies.