205 ILCS 115/2
Any savings and loan or Federal savings and loan association may issue shares, share accounts or accounts in the joint names of two or more persons or their survivor, in which event any of such persons shall have power to act in all matters related to such shares, share accounts or accounts whether the other person or persons named in such shares, share accounts or accounts be living or not. Such a joint account shall create a single membership in any such association. The repurchase or redemption or withdrawal value of shares, share accounts or accounts issued in joint names, and dividends thereon, or other rights relating thereto, may be paid or delivered, in whole or in part, to any of such persons, whether the other person or persons be living or not. The payment or delivery to any such person, or a receipt or acquittance signed by any such person, to whom any such payment or any such delivery of rights is made, shall be a valid and sufficient release and discharge of any such association for the payment or delivery so made.
205 ILCS 115/2