Mo. Rev. Stat. § 33.260

In any year in which a governor-elect assumes office the budget shall be the budget of the new governor and shall be submitted to the general assembly by him. The division of the budget shall render to the governor-elect all possible assistance in the preparation of the budget. The governor and the departments, institutions or agencies of the state shall furnish the governor-elect estimates and other budget information, in order that the governor-elect may discharge effectively his budget responsibilities upon assuming office.