. marathon elected the long-form method to determine its pool of excess tax benefits as of january 1 , 2006 . marathon adopted sfas no . 123 ( r ) as of january 1 , 2006 , for all awards granted , modified or cancelled after adoption and for the unvested portion of awards outstanding at january 1 , 2006 . at the date of adoption , sfas no . 123 ( r ) requires that an assumed forfeiture rate be applied to any unvested awards and that awards classified as liabilities be measured at fair value