Hundreds of thousands of businesses and other entities provide supplies, equipment, and services to federal agencies each year through procurement contracts (contracts). Accurate identification of prospective and incumbent government contractors (or vendors) facilitates the federal government's procurement process, helping to ensure contractors are paid, supporting contract administration activities, enabling the identification of corporate families (e.g., a corporation and its subsidiaries), and, generally, contributing to the transparency of federal government procurement. To aid in accurately identifying the entities with which it does business, the federal government relies on a proprietary system, Dun & Bradstreet's (D&B's) Data Universal Numbering System (DUNS). Dun & Bradstreet assigns unique identification codes known as "DUNS numbers" to prospective federal government contractors. The federal government has used DUNS since at least the early 1990s to meet its needs for an identification system and related services. Whereas the government's continued use of DUNS was supported by the executive branch as recently as 2006, as documented in a Federal Register notice, the federal government has begun exploring alternatives to DUNS and DUNS numbers again. Congress and the executive branch share an interest in containing costs; acquiring, or possibly developing, a nonproprietary identification system; ensuring continued access to, if not outright ownership of, data contained in the identification system; and transparency. Notable legislative initiatives in this area have included passage of the Federal Funding Accountability and Transparency Act (FFATA; P.L. 109-282 ) and the Digital Accountability and Transparency Act (DATA Act; P.L. 113-101 ). The government's change in perspective is reflected in separate, though possibly coordinated, efforts by the General Services Administration (GSA), and the Office of Management and Budget (OMB) and the Department of the Treasury, to examine possible alternatives to DUNS. The Treasury Department-OMB effort is related, as discussed below, to implementation of the DATA Act. The following two sections, " Data Universal Numbering System " and " Commercial and Government Entity (CAGE) System and Codes ," provide basic information about these two systems, respectively. The final section discusses the federal government's reliance on DUNS, interest in and exploration of alternatives to DUNS, and government actions that possibly could pave the way for the adoption of an alternative system, or a hybrid system that includes DUNS. The CAGE system, which is an existing, federal government identification system, may be a candidate for either option. This report focuses on identification numbers for acquisition and acquisition-related purposes that government contractors, generally, are required to have. It does not address taxpayer identification numbers (TINs), which government contractors also are required to have and which are used by the Internal Revenue Service (IRS) in the administration of tax laws. This report also does not cover other types of recipients of federal money (e.g., grant award recipients) who are required to obtain DUNS numbers. Created by Dun & Bradstreet in 1963, DUNS is "a unique global business identification system." The system includes DUNS numbers, which are "nine-digit non-indicative numbering sequence[s] and [are] assigned at the lowest organizational level." As a non-indicative numbering sequence, a nine-digit DUNS number does not in and of itself have any meaning. The lowest organizational level means a "business location[] with a unique, separate and distinct operation." That is, each business location that is a unique, separate, and distinct operation is assigned its own DUNS number. However, some entities have the same, or similar, names. See Figure 1 for an illustrative list of companies and their respective DUNS numbers. A business retains its DUNS number throughout its lifecycle: DUNS numbers do not have an expiration date and D&B neither reissues nor reassigns DUNS numbers. Generally, prospective government contractors are required to register in the federal government's System for Award Management (SAM) prior to the award of a contract, and an entity must have a DUNS number in order to register in SAM. SAM is "the primary Government repository for prospective Federal awardee and Federal awardee information and the centralized Government system for certain contracting, grants, and other assistance-related process." A prospective government contractor may request a DUNS number through an online portal. A company or organization that is required by the federal government to obtain a DUNS number for the purpose of competing for a contract does not pay a fee for its DUNS number. D&B's system, in addition to providing the means for uniquely identifying contractor entities, may be used to "roll-up Government procurements to the ultimate parent organization to show the corporate family receiving U.S. obligations" and contains business-related information. Examples of the types of information contained in the Data Universal Numbering System include number of employees , sales volume, line of business, net worth amount, foreign ownership, liens, history of business, criminal activity indicator, business name change, legal structure, judgments, bankruptcy indicator, credit rating, and parent relationship. DUNS information and services used by the federal government include the names, addresses, and parental linkages of businesses and "logic, corporate research, and corporate business linkage maintenance." The Department of Defense (DOD) created the CAGE system between 1945 and 1950; its original purpose was to catalog various items (e.g., part numbers, National Stock Number, and drawings). Subsequently, other purposes were added, such as using CAGE codes to identify vendors. The CAGE Branch of the Defense Logistics Agency (DLA), which is the only authorized source of these codes, assigns CAGE codes to entities located in the United States or its outlying areas. A CAGE code is a five-character alpha-numeric identifier that belongs to a nonproprietary system created by DOD. Similar to DUNS numbers, some contractors may have the same, or similar, names. See Figure 2 for an illustrative list of companies and their respective CAGE codes. DLA assigns CAGE codes "per legal entity at individual physical addresses (i.e., the same entity at the same physical address will not be assigned two or more CAGE codes)." There is no cost for obtaining a CAGE code. Table 1 compares selected features of DUNS and the CAGE system. DUNS numbers, and the information associated with them, facilitate the smooth, efficient operation of the government's acquisition system. The related products and services that the government obtains from D&B are also integral to the functioning of various procurement processes and activities. (See Appendix A for brief descriptions of the software and data products the federal government purchases from D&B.) Using DUNS, the federal government is able, for example, to uniquely identify the entities that perform work for, or provide supplies or equipment to, agencies; verify contract awardees' information; and track the amount of funds obligated to corporate families. In addition to GSA, which is responsible for many of the federal government's acquisition systems that include or use DUNS numbers and which awards contracts to D&B for the use of DUNS, various federal agencies purchase a variety of D&B services. On June 29, 2010, GSA awarded a sole source contract, under the authority of FAR §6.302-1(a)(2), to Dun & Bradstreet for the use of its Data Universal Numbering System. The contract consists of a three-year base period and five one-year option periods. The effective date of the contract was June 30, 2010; the completion date for the base period was June 29, 2013; and the estimated ultimate completion date (if all five option periods are exercised) is June 29, 2018. The present value of the contract, including the base period and all option periods, if exercised by GSA, is $135,111,119.67. Concerns regarding the cost of using a proprietary service and related issues were publicized in a 2012 Government Accountability Office (GAO) report, which also examined possible alternatives to DUNS and anticipated challenges in replacing DUNS with a different identification system. (See below for a discussion of the GAO report.) GSA explains, in a special notice it posted on the government's Federal Business Opportunities website, why the federal government relies on DUNS numbers and D&B services. The Federal Government, GSA, and Integrated Acquisition Environment have a regulatory mandate to identify and report on corporate relationships and linkages using the DUNS Number as the Contractor Identification Number for Federal Contractors, as set forth in FAR 4.605(b). D&B is the only source that can provide the required identification and reporting services. The DUNS number is proprietary to and controlled by D&B and there is no other source for this information.... No other authoritative sources of corporate enterprises exist today to provide [the] product and services which are uniquely available from the D&B world base files. The logic, corporate research, and corporate business linkage maintenance are all critical services not licensed by D&B to third parties. In the same notice, GSA also describes the extent of the federal government's reliance on D&B services and products.