The following table summarizes the results of operations for our financial guaranty segment for the years ended  December 31, 2012, 2011 and 2010:  Net (Loss) Income. Our financial guaranty segment results for  2012 and 2010 were impacted primarily by realized and  unrealized losses in the change in fair value of derivative instruments and net losses on other financial instruments. Our credit  spread tightened in 2010 and 2012 compared to 201 1, when our credit spread widened, resulting in unrealized gains.  The net  loss for 2012 also was impacted by the CDO Commutation Transactions and by the Assured Transaction, which reduced our  pre-tax income by $28.8 million. Our 2011 results were impacted by an income tax benefit compared to an income tax  provision in 2012 and an income tax provision in 2010 as a result of our establishment of a valuation allowance in  2010. __________________ n/m—not meaningful Year Ended December 31, % Change ($ in millions) 2012 2011 2010 2012 vs. 2011 2011 vs. 2010 Net (loss) income . . . . . . . . . . . . . . . . . . . . . . . . . . $ (236.9) $ 946.1 $ (695.4) n/m n/m Net premiums written—insurance. . . . . . . . . . . . . (119.7) (10.0) (8.0) n/m 25.0 % Net premiums earned—insurance. . . . . . . . . . . . . . 36.6 75.1 86.1 (51.3)% (12.8)% Net investment income. . . . . . . . . . . . . . . . . . . . . . 51.1 69.8 74.7 (26.8) (6.6) Net gains on investments . . . . . . . . . . . . . . . . . . . . 81.2 76.0 55.9 6.8 36.0 Change in fair value of derivative instruments . . . . (143.7) 629.0 (591.1) n/m n/m Net (losses) gains on other financial instruments. . (78.8) 189.4 (163.6) n/m n/m Gain on sale of affiliate . . . . . . . . . . . . . . . . . . . . . . 7.7 — — n/m n/m Other income . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 0.2 0.4 50.0 (50.0) Provision for losses. . . . . . . . . . . . . . . . . . . . . . . . . 37.7 2.7 8.4 n/m (67.9) Policy acquisition costs. . . . . . . . . . . . . . . . . . . . . . 27.7 16.7 17.4 65.9 (4.0) Other operating expenses. . . . . . . . . . . . . . . . . . . . 44.2 43.6 50.5 1.4 (13.7) Interest expense . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.4 47.5 30.1 (6.5) 57.8 Income tax provision (benefit). . . . . . . . . . . . . . . . 37.3 (16.8) 51.5 n/m n/m 128