Colo. Rev. Stat. § 11-57-102
The securities described in section 11-57-101 shall be in such registered or bearer form, with or without interest coupons; be subject to such conditions for transfer; be subject to such provisions for conversion as to denomination or to bearer or registered form; be made registerable or payable, or both, by the treasurer or other officer of the issuing entity, or by such trustee, registrar, paying agent, or transfer agent within or without this state; be issued, transferred, and registered by such book entry; be in such denomination or denominations; bear such dates, signatures, and authentications; and be held in custody by such depository within or without this state, all as may be determined by the entity or the governing body of the entity authorized or empowered to issue such securities. Payment at designated due dates or in installments may be required by the authorizing proceedings to be by check, draft, or other medium of payment and need not be conditioned upon presentation of any security or coupon. Signatures on any printed securities issued under this article or any other statute may be manually subscribed or by facsimile, but any such printed security, other than an interest coupon, shall bear at least one manual signature, which, notwithstanding the provisions of section 11-55-103(1) or any other law, may be that of an official of the issuing entity or of the trustee, registrar, or transfer agent.
C.R.S. § 11-57-102