ISP (Internet Service Provider)

What It Means

An Internet Service Provider (ISP) is any company that sells internet access to consumers, businesses, or other organizations. The U.S. broadband market is highly concentrated: the top five ISPs (Comcast, Charter, AT&T, Verizon, and T-Mobile) serve roughly 80% of all U.S. fixed broadband subscriptions. Comcast Xfinity leads with approximately 32 million residential subscribers, Charter Spectrum second with about 30 million, together controlling over 55% of the cable broadband market. AT&T serves 14 million wired customers (split between AT&T Fiber and legacy DSL), Verizon serves 7.5 million Fios and DSL subscribers plus 4.6 million 5G Home Internet fixed wireless customers, and T-Mobile has grown to 5.4 million FWA subscribers. Second-tier players include Lumen (CenturyLink), Frontier Communications, Windstream (Kinetic), Cox Communications, Altice (Optimum, Suddenlink), Mediacom, and Cable One (Sparklight). Thousands of regional and municipal ISPs serve specific markets, including notable fiber-first operators like Google Fiber, Ziply Fiber, Sonic, EPB Chattanooga, and hundreds of rural telephone cooperatives. Many ZIP codes have only one or two wired ISPs available at any given address, a consequence of the high fixed costs of last-mile deployment. Fixed wireless access from T-Mobile and Verizon has meaningfully expanded competition in many markets since 2021. The Broadband Grade weights provider competition at 30% of the total score because FCC data consistently shows that ZIP codes with three or more broadband providers see 20 to 40% lower average prices and 30 to 50% higher average speeds than monopoly or duopoly markets.

Frequently Asked Questions