(Millions of dollars, unless otherwise indicated) Notes to consolidated financial statements  September 27, 2014 and September 28, 2013 17. GOODWILL For  impairment testing, the carrying amount of goodwill was allocated to the unique operating segment of the Corporation.  The recoverable amount was determined based on its value in use, which was calculated using pre-tax cash flow  forecasts  from the management-approved budgets. The forecasts reflected past experience. A pre-tax discount rate of  14.1 %  was used and any growth rate was taken into consideration. Key assumptions for fiscal 2014 and 2013 were  similar .  No reasonably possible change of any of these assumptions would result in a carrying amount higher than the  recoverable amount. As at September 27, 2014 and September 28, 2013, the Corporation's only bank loans were the credit margins of  structured  entities. The consolidated structured entities have credit margins totaling $7.9 ($7.7as at September 28, 2013),  bearing  interest at prime, unsecured and maturing on various dates through 2015. As at September 27, 2014, $1.5 ($2.0 as at September 28, 2013 ) had been drawn down under credit margins at an interest rate of 3.5 % ( 3.0% as at  September 28, 2013 ). - 68 - 2014  2013 Balance – beginning of year 1,855.6 1,859.5 Acquisitions —  0.1 Acquisitions through business combinations  (note 5)  91.1  — Disposals related to the discontinued operation  (note 8)  —  (4.0) Disposals (0.1 )  — Balance – end of year 1,946.6  1,855.6 18. BANK LOANS 19. OFFSETTING 2014  2013 Accounts payable (gross) 1,033.7  1,052.4 Vendor rebate receivables (51.0 )  (47.5) Accounts payable (net) 982.7 1,004.9