The State Treasurer shall be the custodian of the Old Fund, the Uninsured Employer Fund, the Self-Insured Employer Guaranty Risk Pool, and the Self-Insured Employer Security Risk Pool, and moneys payable to each of these funds shall be deposited in the State Treasury to the credit of the funds. Each fund shall be a separate and distinct fund upon the books and records of the Auditor and Treasurer. Disbursements from these funds shall be made upon requisitions signed by the Insurance Commissioner. The Old Fund, the Uninsured Employer Fund, the Self-Insured Employer Guaranty Risk Pool, and the Self-Insured Employer Security Risk Pool are participant plans as defined in § 12-6-2 of this code and are subject to the provisions of § 12-6-9a of this code. The funds may be invested by the Investment Management Board in accordance with § 12-6-1 et seq. of this code.