132 NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS OF AEGON N.V.  NOTE 4 Comparative information on subprime ABS mortgage exposure  by quality and vintage - 2009 figures: 1  Second lien collateral primarily composed of loans to prime and Alt-A borrowers. Residential mortgage backed securities Additionally, AEGON USA has exposure to ABS collateralized by  manufactured housing loans. The market value of these securities  is EUR 125 million (2009: EUR 122 million) with an amortized  cost balance of EUR 132 million (2009: EUR 135 million). All but  three positions have vintages of 2003 or prior. These amounts  are not included in AEGON’s subprime mortgage exposure  tables above.  Where credit events may be impacting the unrealized losses,  cash flows are modelled using effective interest rates. AEGON  did not consider those securities to be impaired. Refer to note 3  for details on the pricing process.  AEGON USA holds EUR 4,121 million (2009: EUR 3,572 million)  of RMBS. RMBS are securitizations of underlying pools of non- commercial mortgages on real estate. The underlying residential  mortgages have varying credit ratings and are pooled together  and sold in tranches. The Group’s RMBS mainly includes  government sponsored enterprise (GSE) guaranteed  passthroughs, whole loan passthroughs, Alt-A MBS and negative  amortization MBS.  All RMBS securities are monitored and reviewed on a monthly  basis with detailed modeling completed on each portfolio  quarterly. Model output is generated under base and several  stress-case scenarios. RMBS asset specialists utilize modeling  software to perform a loan-by-loan, bottom-up approach to  modeling. Models incorporate external loan-level analytics to  identify the riskiest securities. The results from the models  are then closely analyzed by the asset specialist to determine  whether or not a principal or interest loss is expected to occur.  Positions are impaired to fair value where loss events have  taken place (or are projected to take place on structured  securities) that would affect future cash flows. The tables  below summarize the credit quality of these securities based  on a hierarchy of S&P, Moody's, Fitch, internal and NAIC of  the RMBS portfolio.  AAA AA A BBB  < BBB   Total  Of which  insured Pre-2005 314 36 9 – 42 401 82 2005 118 8 19 – 3 148 – 2006 15 – – 7 69 91 17 2007 124 – – 2 85 211 96 2008 17 – – – – 17 17 Total subprime mortgages -  Fixed rate 588 44 28 9 199 868 212 Pre-2005 17 19 2 13 17 68 30 2005 60 40 – 19 13 132 – 2006 11 46 – 3 87 147 – 2007 14 15 – – 126 155 17 2008 16 – – – – 16 16 Total subprime mortgages -  Floating rate 118 120 2 35 243 518 63 Pre-2005 51 8 8 27 8 102 47 2005 – – – 27 13 40 40 2006 – 4 9 8 51 72 72 2007 6 – – – 199 205 204 Total second lien mortgages 1 57 12 17 62 271 419 363 AT DECEMBER 31, 2009 763 176 47 106 713 1,805 638 Amortized cost by Quality and Vintage