A contract of use where the parties enter into transactions involving the purchase or sale of mortgage-backed securities and other securities that may be determined, including under issuance, TBA, dollar roll and other transactions that may result in or lead to the late delivery of securities. Press Release › A user agreement in which the parties may enter into transactions in which one party (a “Seller”) agrees to transfer securities or other assets to the other (a “Buyer”) against the transfer of funds by buyer, with Buyer`s simultaneous agreement to transfer such securities to seller at any given time or upon request; against the transfer of funds by the seller.