15 U.S.C. § 1526: Receipts for work or services; deposit in special accounts; availability for payment of costs, repayment or advances to appropriations or funds, refunds, credits to working capital funds; appropriation limitation of annual expenditures from accounts

All payments for work or services performed or to be performed under this Act shall be deposited in a separate account or accounts which may be used to pay directly the costs of such work or services, to repay or make advances to appropriations or funds which do or will initially bear all or part of such costs, or to refund excess sums when necessary: Provided , That said receipts may be credited to a working capital fund otherwise established by law, and used under the law governing said funds, if the fund is available for use by the agency of the Department of Commerce which is responsible for performing the work or services for which payment is received. Acts appropriating funds to the Department of Commerce may include provisions limiting annual expenditure from said account or accounts.