31 USC 3525 – Auditing nonappropriated fund activities
(a) The Comptroller General may audit—
(1) the operations and accounts of each nonappropriated fund and related activities authorized or operated by the head of an executive agency to sell goods or services to United States Government personnel and their dependents;
(2) accounting systems and internal controls of the fund and related activities; and
(3) internal or independent audits or reviews of the fund and related activities.
(b) The head of each executive agency promptly shall provide the Comptroller General with—
(1) a copy of the annual report of a nonappropriated fund and related activities subject to this section when the Comptroller General—
(A) requires a report for a designated class of each fund and related activities having gross sales receipts of more than $100,000 a year; or
(B) specifically requests a report for another fund and related activities; and
(2) a statement on the yearly financial operations, financial condition, and cash flow and other yearly information about the fund and related activities that the head of the agency and the Comptroller General agree on if the information is not included in the annual report.
(c) Records and property of a fund and related activities subject to this section shall be made available to the Comptroller General to the extent the Comptroller General considers necessary.