(REUTERS) -- A review of Research In Motions' leadership structure by a committee of independent directors has concluded that no future chief executive or other employee can be chairperson of the BlackBerry maker.

The panel's findings were published on RIM's Web site late on Monday, a day before a Jan. 31 deadline.

The committee said in its report that it had recommended that RIM should separate the roles of Chair and CEO and amend the board mandate accordingly.

On January 22, the company appointed Barbara Stymiest, who formerly served as a member of Royal Bank of Canada's Group Executive, as independent board chair.

Company investors led by Northwest & Ethical Investments LP had demanded that RIM name an independent chairman, a role previously shared by co-Chief Executive Officers Jim Balsillie and Mike Lazaridis, to ensure the board acted independently of management.

Lazaridis and Balsillie stepped down just over a week ago but will remain on the board.