All secu­ri­ty trans­ac­tions, includ­ing col­lat­er­al for repur­chase agree­ments, entered into by the Coun­ty, shall be con­duct­ed on a deliv­­ery-ver­­sus-pay­­ment (DVP) basis.  Secu­ri­ties will be held by an inde­pen­dent third par­ty cus­to­di­an des­ig­nat­ed by the Trea­sur­er and evi­denced by safe­keep­ing receipts and a writ­ten cus­to­di­al agreement.