26 C.F.R. § 1.592-1
There is deductible, under section 592, from the gross income of a mutual savings bank not having capital stock represented by shares, a domestic building and loan association, or a cooperative bank without capital stock organized and operated for mutual purposes and without profit, amounts paid by such institutions during the taxable year in repayment of loans made before September 1, 1951, by the United States or any agency or instrumentality thereof which is wholly owned by the United States, or by any mutual fund established under the authority of the laws of any State. For example, amounts paid by such institution in repayment of loans made by the Reconstruction Finance Corporation before September 1, 1951, are deductible under this section. Section 592 is not applicable, however, in the case of amounts paid in repayment of loans made by an agency or instrumentality not wholly owned by the United States.
26 C.F.R. §1.592-1