Research in Motion will restate three years of earnings following an internal stock options probe, the company said today. The aggregate effect of the revisions will lop $250m off RIM's historic earnings.

As another consequence of the options probe co-CEO Jim Balsille, who unusually, shares the role with RIM founder Mike Lazaridis, will relinquish his job as chairman. He continues in the joint-CEO capacity, however, and Lazaridis is permitted to keep his other role of President.

RIM said the hat switch is designed to ensure the company conforms to "current best practices" in corporate governance.

RIM announced that it was investigating the backdating of options last September. The internal options probe found Balsille responsible for backdated options grants which were not correctly accounted for, including some granted for RIM's public flotation ten years ago. Both Balsille and Lazardis said they'll cover the cost of the investigation personally.

John Richardson assumes the role of board chairman, on an expanded board.

RIM reported a net income of $176m on revenue of $835m in its most recent quarter, ending December 2. ®