Apple Inc. said mobile software head Scott Forstall and retail chief John Browett are departing as Chief Executive Officer Tim Cook embarks on a sweeping management overhaul at the world's most valuable company.

Forstall will leave next year and serve as an adviser to Cook until then, Cupertino, California-based Apple said yesterday in a statement. Executives Jony Ive, Eddy Cue, Bob Mansfield and Craig Federighi will take on added management responsibilities, the company said. Forstall was pushed out, according to a person with knowledge of the dismissal who asked not to be identified because the matter is private.

Forstall oversaw products such as mapping software and the Siri voice-recognition tool, which met with criticism. He also frequently clashed with other managers, people with knowledge of the matter have said. Cook, who succeeded co-Founder Steve Jobs last year, is revamping leadership as Apple's stock price sags and competition accelerates from rivals including Google Inc., Microsoft Corp. and Amazon.com Inc.