C.R.S. § 24-75-208

It is lawful for the state treasurer and it is the state treasurer’s duty, whenever there are funds on hand or in the state treasurer’s custody or possession eligible for investment, to invest in noninterest bearing general fund warrants or checks issued against the general fund at a time when moneys accruing to the fund have not been received or credited to the general fund, but such warrants or checks shall be drawn pursuant to appropriation made by the general assembly, and the controller shall first certify that appropriations do not exceed estimated general fund revenues and surplus.