California Code, Vehicle Code - VEH § 42273

By the 10th day of each calendar month, the balance remaining to the credit of the Motor Vehicle Account in the State Transportation Fund at the close of business on the last day of the preceding calendar month, after payments of refunds and administration and enforcement, that is not needed for immediate use from the Motor Vehicle Account shall, on order of the State Controller, be transferred to the credit of the State Highway Account in the State Transportation Fund.