6 U.S. Code § 296 - Separation of funding
There shall be established separate accounts in the Treasury of the United States for appropriated funds and other deposits available for the Bureau of Citizenship and Immigration Services and the Bureau of Border Security.
To ensure that the Bureau of Citizenship and Immigration Services and the Bureau of Border Security are funded to the extent necessary to fully carry out their respective functions, the Director of the Office of Management and Budget shall separate the budget requests for each such entity.
Fees imposed for a particular service, application, or benefit shall be deposited into the account established under subsection (a) that is for the bureau with jurisdiction over the function to which the fee relates.
No fee may be transferred between the Bureau of Citizenship and Immigration Services and the Bureau of Border Security for purposes not authorized by section 1356 of title 8.
Bureau of Border Security, referred to in subsecs. (a), (b), and (d), changed to Bureau of Immigration and Customs Enforcement by Reorganization Plan Modification for the Department of Homeland Security, eff. Mar. 1, 2003, H. Doc. No. 108–32, 108th Congress, 1st Session, set out as a note under section 542 of this title.