Exhibit A Underlying Certificates Trust Asset Group Issuer Series Class Issue Date CUSIP Number Interest Rate Interest Type(1) Final Distribution Date Principal Type(1) Original Principal or Notional Balance of Class Underlying Certificate Factor(2) Principal or Notional Balance in the Trust Percentage of Class in Trust Approximate Weighted Average Coupon of Mortgage Loans Approximate Weighted Average Remaining Term to Maturity of Mortgage Loans (in months) Approximate Weighted Average Loan Age of Mortgage Loans (in months) Ginnie Mae I or II 3 Ginnie Mae  2003-070 KO 8/29/2003  38374BC84 0.0% PO August 2033 SUP $ 5,225,000   1.00000000   $  5,225,000 100.0000000000% 5.417% 347 10 II 3 Ginnie Mae  2003-070 BP 8/29/2003  38374BM34 0.0 PO May 2031 SUP 1,316,667 1.00000000 359,091 27.2727272727% 5.417 347 10 II 3 Ginnie Mae  2003-070 BO 8/29/2003   38374BL68 0.0 PO November 2030 SUP 4,200,000 0.68466296 784,250 27.2727380952% 5.417 347 10 II 3 Ginnie Mae  2004-021 YD 4/30/2004  38374FX33 5.0 FIX April 2034 PAC II 2,860,000 1.00000000 1,280,000 44.7552447552% 5.588 355 2 II 4 Ginnie Mae  2003-113 AI 12/30/2003    38374EJ32 4.5 FIX/IO August 2026 NTL (SEQ/AD) 472,640,000 0.95613538 796,780 0.1763147427% 5.000 345 9 I 4 Ginnie Mae  2003-097 IV 11/28/2003  38374EYM3 4.5 FIX/IO  September 2025 NTL (PAC) 9,888,888 1.00000000 4,944,444 50.0000000000% 5.000 346 9 I 7 Ginnie Mae  2003-062 IB 7/30/2003  38374BEZ2 5.0 FIX/IO May 2033 NTL (PAC) 12,764,882 1.00000000 1,500,000 11.7509899426% 5.595 346 11 II 7 Ginnie Mae  2004-021 PI 4/30/2004   38374FY24 5.0 FIX/IO June 2025 NTL (PAC I) 20,430,000 0.99214881 1,488,223 7.3421439060% 5.588 355 2 II 7 Ginnie Mae  2003-070 IL 8/29/2003  38374BH71 5.0 FIX/IO  September 2021 NTL (PAC) 12,000,000 0.74706685 4,482,401 50.0000000000% 5.417 347 10 II 8 Ginnie Mae  2003-018 IC 3/28/2003  38373SM38 5.5 FIX/IO  September 2024 NTL (PAC I) 13,272,727 1.00000000 454,545 3.4246541800% 6.271 340 15 II 8 Ginnie Mae  2003-010 IC 2/28/2003  38373SGD3 5.5 FIX/IO June 2028 NTL (PAC I) 75,600,000 1.00000000 5,054,545 6.6859060847% 6.260 340 16 II 8 Ginnie Mae 2002-79 IA 11/29/2002  38373YCM4 5.5 FIX/IO  September 2026 NTL (SEQ) 246,000,000 0.39686965 2,705,929 2.7716186992% 6.292 337 20 II 8 Ginnie Mae  2003-010 MI 2/28/2003  38373SGB7 5.5 FIX/IO August 2025 NTL (PAC I) 42,960,000 1.00000000 9,443,636 21.9823929236% 6.260 340 16 II 8 Ginnie Mae 2002-79 ID 11/29/2002  38373YEC4 5.5 FIX/IO February 2030 NTL (SEQ) 328,000,000 0.54765224 5,437,689 3.0271618902% 6.292 337 20 II 9 Ginnie Mae  2003-070 NI 8/29/2003  38374BW58 5.5 FIX/IO August 2029 NTL (PAC I) 66,300,000 1.00000000 4,104,545 6.1908672700% 5.954 345 11 II 9 Ginnie Mae  2003-046 IA 6/30/2003  38373Q4L2 5.5 FIX/IO April 2023 NTL (PAC I) 10,487,272 1.00000000 7,865,455 75.0000095354% 6.252 342 13 II 9 Ginnie Mae  2003-028 IN 4/30/2003  38373QBR1 5.5 FIX/IO   December 2026 NTL (PAC I) 23,181,818 1.00000000 9,865,000 42.5549022945% 6.256 342 14 II 10 Ginnie Mae  2003-046 IG 6/30/2003  38373Q4Z1 5.5 FIX/IO August 2030 NTL (PAC I) 3,168,727 1.00000000 125,000 3.9448018084% 6.252 342 13 II 10 Ginnie Mae  2003-076 IE 9/30/2003  38374CNK3 5.5 FIX/IO February 2033 NTL (PAC I) 21,876,363 1.00000000 145,454 0.6648911430% 5.913 346 10 II 10 Ginnie Mae  2003-040 IN 5/30/2003  38373QZZ7 5.5 FIX/IO   November 2032 NTL (PAC I) 15,045,454 1.00000000 4,795,455 31.8731159591% 6.251 342 13 II 11 Ginnie Mae  2003-062 KI 7/30/2003  38374BMB6 5.5 FIX/IO June 2033 NTL (PAC/AD) 196,200,000 0.93823169 2,132,345 1.1583730887% 6.256 344 12 II 11 Ginnie Mae  2003-062 MI 7/30/2003  38374BGR8 5.5 FIX/IO June 2033 NTL (PAC/AD) 28,800,000 0.93185805 7,319,322 27.2727291667% 6.256 344 12 II 12 Ginnie Mae  2003-040 IB 5/30/2003  38373QD32 5.5 FIX/IO March 2030 NTL (PAC) 17,150,356 1.00000000 195,487 1.1398422283% 6.000 342 13 I 12 Ginnie Mae  2004-017 MI 3/30/2004  38374FG65 5.5 FIX/IO February 2032 NTL (PAC/AD) 115,909,090 0.99066289 28,706,709 25.0000004314% 6.000 345 10 I 13 Ginnie Mae  2003-097 LI 11/28/2003  38374EXS1 6.0 FIX/IO April 2033 NTL (PAC/AD) 14,583,333 0.92222371 5,379,638 39.9999986286% 6.790 326 29 II 13 Ginnie Mae 2002-60 KI 8/30/2002   38373VJP6 6.0 FIX/IO March 2027 NTL (SEQ/AD) 50,000,000 0.29404173 1,837,761 12.5000000000% 6.803 300 52 II 13 Ginnie Mae  2003-076 UI 9/30/2003    38374CJS1 7.5 FIX/IO February 2027 NTL (PAC I/AD) 107,360,000 0.74939530 11,990,324 14.9031296572% 6.791 323 31 II (1)  As defined under "Class Types" in Appendix I to the Base Offering Circular. (2)  Underlying Certificate Factors are as of May 2004. A-1