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,because if the proceeds from the sale did not arrive, the customer would still
have to pay for the purchased shares.