Pandora Co-Founder Tim Westergren Returns as CEO

Shares of Pandora plunged Monday as news that co-founder Tim Westergren was returning as chief executive failed to ignite confidence in the group’s long-term prospects. Westergren, who helped found the Internet radio service in the early 2000s and served as chief executive from 2002 to 2004, replaces Brian McAndrews, who …