EXHIBIT 12.01 Ambac Financial Group, Inc. Ratio of Earnings to Fixed Charges (In thousands, except ratios) Years Ended December 31, --------------------------------------------------------- 2000 1999 1998 1997 1996 --------------------------------------------------------- Earnings: Income before income taxes $482,124 $404,658 $328,912 $285,996 $375,506 Interest expense 37,477 36,525 32,761 21,346 20,925 Portion of rentals deemed to be interest 1,859 1,782 1,846 1,699 1,287 --------------------------------------------------------- Earnings $521,460 $442,965 $363,519 $309,041 $397,718 ========================================================= Fixed Charges: Interest Expense $37,477 $36,525 $32,761 $21,346 $20,925 Portion of rentals deemed to be interest 1,859 1,782 1,846 1,699 1,287 --------------------------------------------------------- Fixed Charges $39,336 $38,307 $34,607 $23,045 $22,212 ========================================================= Ratio of earnings to fixed charges 13.3 11.6 10.5 13.4 17.9 =========================================================