A "government instrumentality" is not defined in the tax code. Rev. Rul. 57-128, 1957-1 C. B. 311. articulates six criteria to identify instrumentalities:
- whether it is used for a governmental purpose and performs a governmental function;
- whether performance of its function is on behalf of one or more states or political subdivisions;
- whether there are any private interests involved, or whether the states or political subdivisions involved have the powers and interests of an owner;
- whether control and supervision of the organization is vested in public authority or authorities;
- if express or implied statutory or other authority is necessary for the creation and/or use of such an instrumentality, and whether such authority exists; and
- the degree of financial autonomy and the source of its operating expenses.
Follow this link for a more detailed definition of government instrumentality
