USC Subchapter I

31 U.S.C. § 1501 Documentary evidence requirement for Government obligations

(a) An amount shall be recorded as an obligation of the United States Government only when supported by documentary evidence of—(1) a binding agreement between an agency and another person (including an agency) that is—(A) in writing, in a way and form, and for a purpose authorized by law; and (B) executed before the end of the period of availability for obligation of the appropriation or fund used for specific goods to be delivered, real property to be bought or leased, or work or service to be provided; (2) a loan agreement showing the amount and terms of repayment; (3) an order required by law to be placed with an agency; (4) an order issued under a law authorizing purchases without advertising—(A) when necessary because of a public exigency; (B) for perishable subsistence supplies; or (C) within specific monetary limits; (5) a grant or subsidy payable—(A) from appropriations made for payment of, or contributions to, amounts required to be paid in specific amounts fixed by law or under formulas prescribed by law; (B) under an agreement authorized by law; or (C) under plans approved consistent with and authorized by law; (6) a liability that may result from pending litigation; (7) employment or services of persons or expenses of travel under law; (8) services provided by public utilities; or (9) other legal liability of the Government against an available appropriation or fund. (b) A statement of obligations provided to Congress or a committee of Congress by an agency shall include only those amounts that are obligations consistent with subsection (a) of this section.

31 U.S.C. § 1502 Balances available

(a) The balance of an appropriation or fund limited for obligation to a definite period is available only for payment of expenses properly incurred during the period of availability or to complete contracts properly made within that period of availability and obligated consistent with section 1501 of this title. However, the appropriation or fund is not available for expenditure for a period beyond the period otherwise authorized by law. (b) A provision of law requiring that the balance of an appropriation or fund be returned to the general fund of the Treasury at the end of a definite period does not affect the status of lawsuits or rights of action involving the right to an amount payable from the balance.

31 U.S.C. § 1503 Comptroller General reports of amounts for which no accounting is made

The Comptroller General shall make a special report each year to Congress on recommendations for changes in laws, that the Comptroller General believes may be in the public interest, about amounts— (1) for which no accounting is made to the Comptroller General; and (2) that are in—(A) accounts of the United States Government; or (B) the custody of an officer or employee of the Government if the Government is financially concerned.