31 U.S.C. § 1106: Supplemental budget estimates and changes

substantial changes in or reappraisals of estimates of expenditures and receipts; substantial obligations imposed on the budget after its submission; current information on matters referred to in section 1105(a)(8) and (9)(B) and (C) of this title; and additional information the President decides is advisable to provide Congress with complete and current information about the budget and current estimates of the functions, obligations, requirements, and financial condition of the United States Government; for the 4 fiscal years following the fiscal year for which the budget is submitted, information on estimated expenditures for programs authorized to continue in future years, or that are considered mandatory, under law; and for future fiscal years, information on estimated expenditures of balances carried over from the fiscal year for which the budget is submitted. Before July 16 of each year, the President shall submit to Congress a statement of changes in budget authority requested, estimated budget outlays, and estimated receipts for the fiscal year for which the budget is submitted (including prior changes proposed for the executive branch of the Government) that the President decides are necessary and appropriate based on current information. The statement shall include the effect of those changes on the information submitted under section 1105(a)(1)–(14) and (b) of this title and shall include supporting information as practicable. The statement submitted before July 16 may be included in the information submitted under subsection (a)(1) of this section. Subsection (f) of section 1105 shall apply to revisions and supplemental summaries submitted under this section to the same extent that such subsection applies to the budget submitted under section 1105(a) to which such revisions and summaries relate.