human: In view of the Patent Term Guarantee, does the United States Patent and Trademark Office plan to print an explicit indication of the expiration date on the face of a patent so that the expiration date can be ascertained without having to add the patent t
assistant: The United States Patent and Trademark Office does not print the expiration date on issued patents because the actual date a patent will expire is dependent upon a number of future events. The actual date any particular patent will expire is, for example, dependent upon whether: (1) all maintenance fees are timely paid; (2) the patent is disclaimed, either by a statutory disclaimer of all claims or a terminal disclaimer; (3) all of the claims of the patent are canceled during a reexamination proceeding; or (4) an extension under 35 U.S.C. 156 is granted. Since less than forty percent of patentees pay all three maintenance fees, an expiration date based upon a calculation of date that is twenty years from the earliest filing date under 35 U.S.C. 111(a), 120, 121, 363, or 365(c) plus any calculated extension under 35 U.S.C. 154(b) would be incorrect and misleading over sixty percent of the time. However, the front page of the patent will indicate the number of days of term adjustment to which the patent is entitled.