Bills of exchange, also referred to as bills, are essentially a short term credit instrument that can be used by a company either for financing or investment. Bills can be issued for any term up to a year and are generally issued for periods of less than 6 months. Companies issue bills because they are a convenient form of borrowing. The difference between bills and a standard loan is that bills held by the bank can sold to investors. Bills with terms of 30 days to 90 days are the easiest to trade? Bills are usually an ideal loan because a company generally will not run into any problems within 3 to 6 months.