Security Group 3 PSA Prepayment Assumption Rates Class CA Class CB Classes JF, JS, KS, MO and SJ Class MA Distribution Date 0% 100% 225% 300% 500% 0% 100% 225% 300% 500% 0% 100% 225% 300% 500% 0% 100% 225% 300% 500% Initial Percent ..................     100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 August 2008......................    100 100 91 85 67 100 100 100 100 100 98 95 95 95 95 100 100 88 80 59 August 2009......................    100 100 74 55 7 100 100 100 100 100 96 87 87 87 87 100 100 65 42 0 August 2010......................    100 100 54 23 0 100 100 100 100 0 94 76 76 76 73 100 100 40 2 0 August 2011......................    100 100 40 1 0 100 100 100 100 0 92 67 67 67 50 100 100 21 0 0 August 2012......................    100 100 30 0 0 100 100 100 56 0 90 58 58 58 35 100 100 7 0 0 August 2013......................    100 100 22 0 0 100 100 100 27 0 87 49 49 49 24 100 100 0 0 0 August 2014......................    100 100 16 0 0 100 100 100 7 0 85 41 41 41 16 100 100 0 0 0 August 2015......................    100 100 12 0 0 100 100 100 0 0 82 34 34 34 11 100 100 0 0 0 August 2016......................    100 100 10 0 0 100 100 100 0 0 79 27 27 27 8 100 100 0 0 0 August 2017......................    100 100 7 0 0 100 100 100 0 0 76 22 22 22 5 100 100 0 0 0 August 2018......................    100 100 4 0 0 100 100 100 0 0 72 17 17 17 4 100 100 0 0 0 August 2019......................    100 100 1 0 0 100 100 100 0 0 69 14 14 14 2 100 100 0 0 0 August 2020......................    100 96 0 0 0 100 100 91 0 0 65 11 11 11 2 100 98 0 0 0 August 2021......................    100 88 0 0 0 100 100 80 0 0 61 9 9 9 1 100 88 0 0 0 August 2022......................    100 79 0 0 0 100 100 70 0 0 56 7 7 7 1 100 77 0 0 0 August 2023......................    100 71 0 0 0 100 100 61 0 0 51 5 5 5 1 100 66 0 0 0 August 2024......................    100 62 0 0 0 100 100 52 0 0 46 4 4 4 0 100 55 0 0 0 August 2025......................    100 53 0 0 0 100 100 44 0 0 41 3 3 3 0 100 45 0 0 0 August 2026......................    100 44 0 0 0 100 100 37 0 0 35 3 3 3 0 100 34 0 0 0 August 2027......................    100 36 0 0 0 100 100 31 0 0 29 2 2 2 0 100 24 0 0 0 August 2028......................    100 28 0 0 0 100 100 26 0 0 23 1 1 1 0 100 14 0 0 0 August 2029......................    100 20 0 0 0 100 100 21 0 0 16 1 1 1 0 100 4 0 0 0 August 2030......................    100 12 0 0 0 100 100 16 0 0 9 1 1 1 0 100 0 0 0 0 August 2031......................    100 5 0 0 0 100 100 13 0 0 1 1 1 1 0 100 0 0 0 0 August 2032...................... 98 0 0 0 0 100 94 10 0 0 0 0 0 0 0 100 0 0 0 0 August 2033...................... 74 0 0 0 0 100 72 7 0 0 0 0 0 0 0 70 0 0 0 0 August 2034...................... 48 0 0 0 0 100 51 4 0 0 0 0 0 0 0 38 0 0 0 0 August 2035...................... 20 0 0 0 0 100 31 3 0 0 0 0 0 0 0 4 0 0 0 0 August 2036...................... 0 0 0 0 0 68 12 1 0 0 0 0 0 0 0 0 0 0 0 0 August 2037...................... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Weighted Average Life (years)  ..................   26.9    18.5 4.1 2.2 1.3 29.2 27.1 18.2 5.4 2.3 15.1 6.9 6.9 6.9 4.7 26.6 17.5 2.7 1.8 1.1 PSA Prepayment Assumption Rates Class MB Class MC Class MD Distribution Date 0% 100% 225% 300% 500% 0% 100% 225% 300% 500% 0% 100% 225% 300% 500% Initial Percent ..................     100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 August 2008......................    100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 August 2009......................    100 100 100 100 11 100 100 100 100 100 100 100 100 100 100 August 2010......................    100 100 100 100 0 100 100 100 100 0 100 100 100 100 0 August 2011......................    100 100 100 0 0 100 100 100 65 0 100 100 100 100 0 August 2012......................    100 100 100 0 0 100 100 100 0 0 100 100 100 74 0 August 2013......................    100 100 84 0 0 100 100 100 0 0 100 100 100 1 0 August 2014......................    100 100 53 0 0 100 100 100 0 0 100 100 100 0 0 August 2015......................    100 100 37 0 0 100 100 100 0 0 100 100 100 0 0 August 2016......................    100 100 32 0 0 100 100 100 0 0 100 100 100 0 0 August 2017......................    100 100 26 0 0 100 100 100 0 0 100 100 100 0 0 August 2018......................    100 100 16 0 0 100 100 100 0 0 100 100 100 0 0 August 2019......................    100 100 0 0 0 100 100 96 0 0 100 100 100 0 0 August 2020......................    100 100 0 0 0 100 100 78 0 0 100 100 100 0 0 August 2021......................    100 100 0 0 0 100 100 61 0 0 100 100 100 0 0 August 2022......................    100 100 0 0 0 100 100 44 0 0 100 100 100 0 0 August 2023......................    100 100 0 0 0 100 100 29 0 0 100 100 100 0 0 August 2024......................    100 100 0 0 0 100 100 15 0 0 100 100 100 0 0 August 2025......................    100 100 0 0 0 100 100 3 0 0 100 100 100 0 0 August 2026......................    100 100 0 0 0 100 100 0 0 0 100 100 88 0 0 August 2027......................    100 100 0 0 0 100 100 0 0 0 100 100 73 0 0 August 2028......................    100 100 0 0 0 100 100 0 0 0 100 100 60 0 0 August 2029......................    100 100 0 0 0 100 100 0 0 0 100 100 48 0 0 August 2030......................    100 71 0 0 0 100 100 0 0 0 100 100 39 0 0 August 2031......................    100 24 0 0 0 100 100 0 0 0 100 100 30 0 0 August 2032......................    100 0 0 0 0 100 83 0 0 0 100 100 22 0 0 August 2033......................    100 0 0 0 0 100 47 0 0 0 100 100 16 0 0 August 2034......................    100 0 0 0 0 100 13 0 0 0 100 100 11 0 0 August 2035......................    100 0 0 0 0 100 0 0 0 0 100 72 6 0 0 August 2036...................... 0 0 0 0 0 40 0 0 0 0 100 27 2 0 0 August 2037...................... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Weighted Average Life (years)  ..................   28.4 23.5 8.0 3.4 1.9 29.0 25.9 14.8 4.2 2.2 29.5 28.5 22.5 5.3 2.4 S-21