B.  Investment Portfolio Scheduled Maturity C. Investment Portfolio by Rating The weighted average duration of the assets in our investment portfolio as of  December 31, 2012 was 4.7 years. The  following table shows the scheduled maturities of the securities held in our investment portfolio at  December 31, 2012: The following table shows the ratings of our investment portfolio as of  December 31, 2012: (1)  Actual maturities may dif fer as a result of calls before scheduled maturity . (2)  RMBS, CMBS and other ABS are shown separately, as they are not due at a single maturity date. (3)  No stated maturity date. (1)  Reflects the highest NRSRO rating assigned to the security as of  December 31, 2012. (3)  Securities in this category have been rated non-investment grade by a NRSRO as of  December 31, 2012. (4)  Includes Limited Partnership investments and a guaranteed investment contract. Fair Value Percent ($ in millions) Rating (1) AAA (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 2,433.8 47.1% AA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480.1 9.3 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,057.6 20.5 BBB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689.5 13.4 BB and below (3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134.8 2.6 Not rated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67.5 1.3 Equity securities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162.4 3.2 Other invested assets (4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.4 2.6 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 5,161.1 100.0% Fair Value Percent ($ in millions) Short-term investments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 777.5 15.1% Due in one year or less (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119.6 2.3 Due after one year through five years (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787.9 15.3 Due after five years through ten years (1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,063.1 20.6 Due after ten years (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 934.9 18.1 RMBS (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663.4 12.9 CMBS (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237.3 4.6 Other ABS (2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254.1 4.9 Other investments (3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323.3 6.2 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 5,161.1 100.0% 41 (2)  Includes $433.8 million of AAA-rated U.S. Government and  Agency securities, $578.8 million in Ginnie Mae securities,  $49.6 million in Freddie Mac securities, and $35.0 million in Fannie Mae securities that have not been rated by a NRSRO  as of December 31, 2012.