Internet radio pioneer Pandora Media Inc. is bringing back co-founder Tim Westergren to run the company as it faces increasing competition from streaming music services such as Apple Music and Spotify.

Westergren will replace Brian McAndrews as chief executive of the Oakland, California-based company. McAndrews was named CEO in 2013.

Pandora’s shares fell $1.33, or 12.2 percent, to close at $9.60 after Pandora announced the change in its leadership.

Westergren first served as CEO from 2002-04 and has remained involved with the company since. Pandora is in the midst of a turnaround plan, having made recent acquisitions including the assets of failed streaming rival Rdio and online ticket seller Ticketfly.