It isn't clear how Mr. Mattrick, 49, who will also join the board, and Mr. Pincus, 47, will steer the company together through the new executive committee, or how they will hash out disagreements, since Mr. Pincus won't directly report to Mr. Mattrick. Mr. Pincus still maintains a strong grip on the company he founded as chairman, and also through his ownership of 61% of the company's voting rights.