Upon the first, second and third anniversaries of the Date of Grant (each, a “Vesting Date”), one-third of the Units that have not been previously forfeited shall become vested. The Human Resources and Compensation Committee of the Company’s Board of Directors (the “Committee”) may, in accordance with the Plan and to the extent permitted by Section 409A of the Code (if applicable), accelerate the vesting period as to some or all of the Units at any time.