Temporary purchases of Treasury Securities are purchases of these assets for a pre-established time period -several days, weeks or months-. In these transactions, the investor purchases Treasury Securities at a certain price to a financial intermediary, who in turn is committed to repurchase the securities after a certain period (usually less than one year) at a pre-set price.

 The return on the investment will be the difference between the sale price and the purchase price of the security. As both prices are "agreed" between both parties at the start of the transaction, the return on the investment is known at the time that the purchase is agreed.

 Temporary purchases of Treasury Securities in Spain can take two forms: repos and sell-buybacks; both alternatives are very similar in all aspects, although repos are used more frequently in the case of small investors.