65 ILCS 5/11-133-4

In case any officer whose signature appears on the specified certificates or the coupons attached thereto ceases to hold his office before the delivery of the certificates to the purchaser, his signature nevertheless shall be valid and sufficient for all purposes, to the same effect as if he had remained in office until the delivery of the certificates. The specified certificates shall have all the qualities of negotiable paper under the law merchant and the negotiable instruments law.