B.  Net Par Outstanding 1.  Aggregate Financial Guaranty Net Par Outstanding Our business has traditionally involved taking credit risk in various forms across various asset classes, products and  geographies. Credit risk is measured in our financial guaranty business as net par outstanding, which represents our  proportionate share of the aggregate outstanding principal exposure on insured obligations.  We are also responsible for the  timely payment of interest on substantially all of our public finance and our non-corporate CDO structured finance insured  financial guaranty obligations. For our insured corporate CDOs and CDOs of CMBS, net par outstanding represents the  notional amount of credit protection we are providing on a pool of obligations.  The following table shows the distribution of our financial guaranty segment’ s net par outstanding by type of exposure  and as a percentage of financial guaranty’ s total net par outstanding, as of the dates indicated.  (1)  Represents our exposure to the aggregate outstanding principal on insured obligations. (2)  Escrowed transactions are legally defeased bond issuances where our financial guaranty policy is not legally extinguished  although cash or securities in an amount suf ficient to pay the remaining obligations under such bonds have been deposited  in an escrow account for the benefit of the bond holders.  Although we have little remaining credit risk on these  transactions, they remain outstanding for GAAP  purposes.  (3)  Represents other types of municipal obligations, including human service providers, second-to-pay international public  finance, non-profit institutions, project finance accommodations and stadiums, none of which individually constitutes a  material amount of our financial guaranty net par outstanding.  (4)  Represents other types of structured finance obligations, including DPRs, collateralized guaranteed investment contracts  or letters of credit, foreign commercial assets and life insurance securitizations, none of which individually constitutes a  material amount of our financial guaranty net par outstanding. 32 December 31, 2012 2011 ($ in billions) Net Par Outstanding (1) % of Total Net Par Outstanding (1) Net Par Outstanding (1) % of Total Net Par Outstanding (1) Type of Obligation Public finance: General obligation and other tax supported. . $ 6.3 18.7% $ 15.8 22.8% Healthcare and long-term care. . . . . . . . . . . . 3.2 9.5 5.4 7.8 Water/sewer/electric gas and investor-owned utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 5.3 3.6 5.2 Education. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 3.6 2.2 3.2 Airports/transportation. . . . . . . . . . . . . . . . . . 1.1 3.2 3.3 4.8 Escrowed transactions (2) . . . . . . . . . . . . . . . 1.0 3.0 1.4 2.0 Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 0.3 0.3 0.4 Other municipal (3) . . . . . . . . . . . . . . . . . . . . 0.6 1.8 0.9 1.3 Total public finance . . . . . . . . . . . . . . . . 15.3 45.4 32.9 47.5 Structured finance: CDO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.5 51.9 35.1 50.7 Asset-backed obligations. . . . . . . . . . . . . . . . 0.8 2.4 0.9 1.3 Other structured (4). . . . . . . . . . . . . . . . . . . . 0.1 0.3 0.3 0.5 Total structured finance. . . . . . . . . . . . . 18.4 54.6 36.3 52.5 Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $ 33.7 100.0% $ 69.2 100.0%