While conventional deposits are generally instruments that are sifted against credit risk, there are residual credit risks. Although this is essentially a guaranteed transaction, the seller may not buy back the securities sold on the due date. In other words, the pension seller does not fulfill his obligation. Therefore, the buyer can keep the warranty and liquidate the guarantee to recover the borrowed money. However, security may have lost value since the beginning of the operation, as security is subject to market movements. To reduce this risk, deposits are often over-insured and subject to a daily market margin (i.e., if the guarantee ends in value, a margin call may be triggered to ask the borrower to reserve additional securities). Conversely, if the value of the guarantee increases, there is a credit risk to the borrower, since the lender is not allowed to resell it. If this is considered a risk, the borrower can negotiate a subsecured repot.  Treasury or Treasury bonds, corporate and treasury bonds, government bonds and equities can all be used as “guarantees” in a repo transaction. However, unlike a secured loan, the right to securities is transferred from the seller to the buyer. Coupons (interest payable to the owner of the securities) that mature while the pension buyer owns the securities are usually passed directly on the seller of securities. This may seem counter-intuitive, given that the legal ownership of the guarantees during the pension agreement belongs to the purchaser. Rather, the agreement could provide that the buyer will receive the coupon, with the money to be paid in the event of a buyback being adjusted as compensation, although this is rather typical of the sale/buyback.
A sale/buy-back is the cash sale and pre-line repurchase of a security. These are two separate pure elements of the cash market, one for settlement in advance. The futures price is set against the spot price in order to obtain a market return. The basic motivation of Sell/Buybacks is generally the same as in the case of a conventional repo (i.e. the attempt to take advantage of the lower financing rates generally available for secured loans, unlike unsecured loans).