When securities are sold by a savings institution subject to an obligation of repurchase, any security interest or interest of ownership therein may be perfected (i) as specified by Title 8.8 or Title 8.9A; (ii) by designation to the person holding physical custody thereof, which shall include a person keeping the master records, in case of securities identified by book entry only, that certain securities identified by serial number or dollar amount are held for the benefit of third parties other than the savings institution, who may, but need not be, identified by name; or (iii) by physical separation on the premises of the savings institution in a separate drawer, compartment, or other facility. The savings institution may, from time to time, instruct any third party holding such securities that the previously identified securities or an amount of such securities previously identified as pledged or belonging to third parties, have been released from such pledge by payment of all or part of the amount due, or have been repurchased. There shall be an identification on the records of the savings institution of the persons who are pledgees or owners of such securities.