Subject to all of the provisions of the Stock Unit Agreement, upon the last day of the Performance Period, the Participant shall become vested in such number of PSUs, if any, as determined under the schedule below, based on the average annual rate of return on equity attained by the Corporation for the Performance Period, but only if the Participant remains continuously employed by the Corporation or one of its Subsidiaries through the last day of the Performance Period; any PSUs that do not become vested in accordance with this Paragraph 4(b) shall be forfeited and revert to the Corporation. The Committee, in its sole and absolute discretion, shall determine the average annual rate of return on equity attained by the Corporation for the Performance Period and certify the percentage of PSUs vested. If the Participant’s employment with Northern Trust is terminated for any reason prior to the end of the Performance Period then, subject to Sections 4(c) and 4(d), the PSUs in the Participant’s Stock Unit Account that have not yet vested shall be forfeited and revert to the Corporation on such employment termination date. Upon the forfeiture of any PSUs, the Corporation shall have no further obligation to the Participant with respect to such PSUs, including the obligation to pay Dividend Equivalents thereon.