This excerpt taken from the SU 6-K filed Jul 2, 2009.
I have lost my Suncor Share certificate or my Petro-Canada Share certificate, what do I do?
All shareholders who have lost their original certificates must duly complete and sign Box A Affidavit of Lost Certificate(s) on the reverse side of the Letter of Transmittal and Election Form and must pay the bond premium by money order or bank draft as outlined therein. The minimum premium is CAD $20.00. If any amount of lost certificates represents (or is expected to represent) a value of Suncor Shares or Petro-Canada Shares of more than CAD $250,000.00, then shareholder(s) should contact Computershare for additional
information. If shareholders lost certificate(s) is (are) part of an estate or trust, please contact Computershare for additional information.