ACA Financial Guaranty provides financial guaranty insurance for municipal and other public finance bonds. Previously, the company also provided asset management services for collateralized debt obligations (CDOs) built by pooling fixed-income assets, including bonds, loans, and credit swaps; investors in the company's CDOs included banks, money managers, hedge funds, and insurance companies. While the company's guaranty business was sound, its other services led to its distress. When the US subprime mortgage market tanked, the company was forced to reorganize and place its municipal bond guaranty business into run-off. Now tending to its existing obligations, ACA is no longer writing new policies.