Symbian Ltd is the software firm that develops and licenses the Symbian OS. Originally spun off from Psion, a maker of PDA devices, the company now focuses on its operating system products. The company is jointly owned by Nokia, Ericsson, Matsushita (AKA Panasonic), Siemens, Sony Ericsson, and Samsung. Motorola was previously a shareholder, but it sold its shares to Psion and Nokia. Nokia later acquired Psion's shares and is now the largest shareholder in the company.