A business improvement district (BID) is a defined area within which businesses are required to pay an additional tax (or levy) in order to fund projects within the district's boundaries. The BID is often funded primarily through the levy but can also draw on other public and private funding streams. BIDs may go by other names, such as business improvement area (BIA), business revitalization zone (BRZ), community improvement district (CID), special services area (SSA), or special improvement district (SID). These districts typically fund services which are perceived by some businesses as being inadequately performed by government with its existing tax revenues, such as cleaning streets, providing security, making capital improvements, construction of pedestrian and streetscape enhancements, and marketing the area. The services provided by BIDs are supplemental to those already provided by the municipality.