D.C. Code § 8-173.47
The bonds of the Authority are legal investments in which public officers and public bodies of the District, insurance companies and associations and other persons carrying on an insurance business, banks, bankers, banking institutions including savings and loan associations, building and loan associations, trust companies, savings banks and savings associations, investment companies and other persons carrying on a banking business, administrators, guardians, executors, trustees, and other fiduciaries and other persons authorized to invest in bonds or in other obligations of the District, may legally invest funds, including capital, in their control. The bonds are also securities that legally may be deposited with and received by public officers and public bodies of the District or any agency of the District for any purpose for which the deposit of bonds or other obligations of the District is authorized by law.
D.C. Code § 8-173.47