The Secretary may make annual contributions to public housing agencies to assist in achieving and maintaining the lower income character of their projects. The Secretary shall embody the provisions for such annual contributions in a contract guaranteeing their payment. The contribution payable annually under this section shall in no case exceed a sum equal to the annual amount of principal and interest payable on obligations issued by the public housing agency to finance the development or acquisition cost of the lower income project involved. Annual contributions payable under this section shall be pledged, if the Secretary so requires, as security for obligations issued by a public housing agency to assist the development or acquisition of the project to which annual contributions relate and shall be paid over a period not to exceed 40 years.

The Secretary may make contributions (in the form of grants) to public housing agencies to cover the development cost of public housing projects. The contract under which such contributions shall be made shall specify the amount of capital contributions required for each project to which the contract pertains, and that the terms and conditions of such contract shall remain in effect for a 40-year period.

The amount of contributions that would be established for a newly constructed project by a public housing agency designed to accommodate a number of families of a given size and kind may be established under this section for a project by such public housing agency that would provide housing for the comparable number, sizes, and kinds of families through the acquisition and rehabilitation, or use under lease, of structures that are suitable for low-income housing use and obtained in the local market.