C.R.S. § 8-79-101

Premiums or surcharges unpaid on the date on which they are due and payable, as prescribed by the division, shall bear interest at the rate of eighteen percent per annum or one and one-half percent per month or any portion thereof on and after such date until payment plus accrued interest is received by the division. Interest collected pursuant to this section shall be paid into the unemployment revenue fund.