Wireless services account for 75% of Verizon Communications' total service revenue and nearly all of its operating income. The firm serves about 94 million postpaid and 20 million prepaid phone customers via its nationwide network, making it the largest US wireless carrier. Fixed-line telecom operations include local networks in the Northeast that reach about 30 million homes and businesses, including about 20 million served by the Fios fiber-optic network. Verizon closed its acquisition of Frontier Communications in January, adding networks that reach another 15 million locations, including 9 million with fiber. These networks serve about 11 million broadband customers. Verizon also provides telecom services nationwide to enterprise customers, using a mix of its own and other networks.