For many types of financial transactions and banking operations. there are temporary imbalances. Cash management systems often allow intra-day overdrafts, and these overdrafts can be large. For instance, a client may send out wire transfers every morning and receive incoming wire transfers every afternoon or may make transfers from different time zones. Every cash management account is supposed to balance at the end of the business day, and if a customer's account shows an overdraft, the amount is supposed to be less than the customer's credit limit. In that same spirit, it is logical that securities trading systems should allow overdrafts that match the length of the delivery period for securities. For example, U.S, stockbrokers allow their customers to sell a stock and then immediately use the proceeds to buy a different one even though the funds from the sale will not arrive until several days later. The customer's account is potentially in overdraft.