A D&B number, also known as a D-U-N-S number, is a nine-digit number that Dun & Bradstreet assigns to each physical location of a company's business, notes Dun & Bradstreet. This number serves as an objective measure of creditworthiness that potential clients use as part of the vendor selection process.
Companies who do business with the U.S. government must include a D-U-N-S number with their application. Once a business receives its D&B number, that number is never assigned to another enterprise. More than 200 trade, industry and global associations either require or recommend the use of this number as of 2015, reports Dun & Bradstreet.