1. Change of fiscal year (a) In general (1) Change of calendar period Section 1102 of title 31, United States Code, is amended— (A) by striking October 1 and inserting January 1 ; and (B) by striking September 30 of the following year and inserting December 31 of that year . (2) Effective date The amendments made by paragraph (1) shall take effect on January 1, 2026. (b) Transition to new fiscal year (1) Transition period budget As soon as practicable, the President shall prepare and submit to Congress— (A) after consultation with the Committee on the Budget and the Committee on Appropriations of the House of Representatives and the Committee on the Budget and the Committee on Appropriations of the Senate, budget estimates for the Federal Government for the period commencing October 1, 2025, and ending on December 31, 2025, in such form and detail as the President may determine; and (B) proposed legislation the President considers appropriate with respect to changes in law necessary to provide authorizations of appropriations for that period. (2) Agency transition The Director of the Office of Management and Budget shall— (A) provide by regulation, order, or otherwise for the orderly transition by all departments, agencies, and instrumentalities of the Federal Government and the government of the District of Columbia from the use of the fiscal year in effect on the date of the enactment of this Act to the use of the new fiscal year prescribed under the amendments made by subsection (a)