This excerpt taken from the HPQ 10-Q filed Jun 8, 2007.
XIII. TERMINATION OF RESTRICTIONS ON STOCK AWARDS
The Committee will establish the period or periods after which the restrictions on Restricted Stock will lapse.
The Committee may in its discretion permit an employee to elect to receive in lieu of shares of Restricted Stock, at the expiration of the restrictions, a cash payment equal to the fair market value of the Companys Common Stock on the date the restrictions lapse. The Committee may also permit the employee to elect to pay required tax withholding due upon the lapse of restrictions with part of the shares due the employee at such time. The shares cancelled in payment of required tax withholding shall be valued at the fair market value of the Companys Common Stock on the date the restrictions lapse. Fair market value shall mean, unless the Committee deems otherwise, as of any date, the closing sales price for such Common Stock as of such date (or if no sales were reported on such date, the closing sales price on the last preceding day on which a sale was made) as reported in such source as the Committee deems reliable.