Gov. Code, § 11258

Any state agency which normally, as a part of its regular operating functions, is engaged in the business of performing work for, or furnishing services, materials or equipment to, other state agencies shall, at its request, be furnished by such other state agencies with a written estimate of the amount which such state agencies expect to expend for such work, services, materials or equipment during a period designated by the state agency requesting said estimate, not exceeding one year. The State Controller from time to time shall transfer the amount so estimated by each state agency, or such portion thereof as he may determine; provided, that he shall transfer any amount ordered by the Director of General Services on the basis of such estimate or otherwise, from the fund or appropriation from which payment is expected to be made for such work, services, materials or equipment to the fund or appropriation of the state agency which is to perform such work, or render such services or furnish any materials or equipment.