AT&T is top business ISP, with Verizon second

Among large businesses, AT&T has a 28 percent share of Internet traffic

AT&T was the biggest Internet service provider for U.S. businesses in September, with 20 percent of the total business Internet traffic, followed by Verizon with a 12 percent share, online tracking and analytics firm comScore said Tuesday.

Even though those two companies controlled 32 percent of the market, many other ISPs compete for the business market and make it more competitive than the residential ISP market, comScore said in a statement. ComScore used browser-based Internet page views as its definition of Internet traffic.

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CenturyLink, which merged with Qwest in April 2011 ranked third among business ISPs with a 7 percent percent share. Following the top three, TW Telecom, Level 3, and Comcast each had 5 percent of the market, while Sprint, TimeWarner Cable, and Cogent each had 4 percent. The 10th largest business ISP was Cox, at 3 percent.

AT&T not only was the overall business ISP leader, the company had the lead in the separate markets, for small, medium and large businesses.

For large businesses, AT&T had a 28 percent share; for medium businesses, 24 percent , and for small businesses, 13 percent. ComScore noted that the small business segment is the most competitive, with 40 percent of the traffic handled by ISPs that rank below the top 10 carriers in that category.

On the large business side, comScore said the top five ISPs had nearly 70 percent of all Internet traffic in September. They were AT&T ( 28 percent), Verizon (19 percent), CenturyLInk (8 percent), Sprint (7 percent) and Level 3 (7 percent).

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed. His email address is

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This story, "AT&T is top business ISP, with Verizon second" was originally published by Computerworld.