Press Releases

November 14, 2011

AT&T Drives Most Internet Traffic for U.S. Businesses in September 2011

Competition Among Business Internet Service Providers (ISPs) Increases as Size of Business Decreases

RESTON, VA, November 14, 2011 – comScore, Inc. (NASDAQ: SCOR), a leader in measuring the digital world, today released an analysis of Internet Service Provider (ISP) market share within businesses across the United States. Among its findings, the study showed AT&T leading the U.S. business ISP market with 20 percent of all browser-based Internet page views (i.e. traffic) in September 2011, followed by Verizon with a 12-percent share of the market. CenturyLink, which merged with Qwest in April 2011, ranked as the third largest business ISP at 7 percent share. The five largest business ISPs drove nearly 50 percent of business Internet traffic across the U.S.

“The current state of the domestic business ISP market reveals a landscape led by a couple of top providers. However, even with smaller carriers contributing only a fraction of the traffic delivered by top carriers, the business ISP market is still more competitive than the residential ISP market,” said Greg Mishkin, comScore Vice President of Telecom and Wireless. “The small business segment is even more competitive among ISPs, highlighting the need for providers to develop strong marketing strategies to ensure they can retain and grow market share.”

Top 10 U.S. Business Internet Service Providers (ISPs)
September 2011
Total U.S.
Source: comScore Business ISP Market Share Report
Business ISP Share (%) of All Business Internet Traffic
AT&T 20%
Verizon 12%
CenturyLink 7%
TW Telecom 5%
Level 3 5%
Comcast 5%
Sprint 4%
Time Warner Cable 4%
Cogent 4%
Cox 3%

Business ISPs See Increased Competition When Catering to Smaller Businesses

A more detailed look into the business ISP market according to the size of businesses being served also reveals AT&T to be the leading business ISP in the large, medium and small business segments. In addition, the top five ISPs accounted for nearly 70 percent of all traffic in the large business segment in September 2011, showing a high concentration of the top providers. In contrast, the share of traffic driven by the top five ISPs was significantly lower within the medium (56 percent) and small business (40 percent) segments.

The small business segment has proven to be the most competitive for business ISPs, with nearly 40 percent of traffic driven by ISPs that rank outside of the top ten carriers for this segment. While AT&T continues to lead all ISPs for small businesses, its 13-percent market share is significantly lower than its share in the large and medium business segments. Comcast (8 percent) and Verizon (7 percent) rounded out the top three ISPs in the small business segment.

Top 10 U.S. Business ISPs According to BusinessSize*
September 2011
Total U.S.
Source: comScore Business ISP Market Share Report
Large Businesses Medium Businesses Small Businesses
ISP Share (%) of Internet Traffic ISP Share (%) of Internet Traffic ISP Share (%) of Internet Traffic
AT&T 28% AT&T 24% AT&T 13%
Verizon 19% Verizon 10% Comcast 8%
CenturyLink 8% TW Telecom 9% Verizon 7%
Sprint 7% CenturyLink 8% CenturyLink 6%
Level 3 7% XO 5% Time Warner Cable 6%
TW Telecom 5% PaeTec Comm. 4% TW Telecom 6%
Internap Network Svcs. 4% Level 3 4% Cogent 5%
Mzima Networks, Inc. 3% Sprint 4% Cox 4%
Global Crossing 2% Cablevision 3% Level 3 4%
XO 2% Windstream 2% PaeTec Comm. 3%
Share for Top 5 ISPs 69% Share for Top 5 ISPs 56% Share for Top 5 ISPs 40%
Share for Top 10 ISPs 85% Share for Top 10 ISPs 73% Share for Top 10 ISPs 62%

*Based on the number of employees per business

AT&T and Verizon Lead Among Business ISPs in the Top Ten U.S. Local Markets

An analysis of the top ten U.S. local markets shows AT&T holding the top position in the majority of these markets in September 2011. Verizon led in 3 of the top 10 markets, including New York, the country’s largest local market. Similar to what was observed at the national level, the competition for business ISPs increases among smaller businesses. In the small business segment, Comcast and AT&T each ranked as the top ISP in 4 of the top 10 local markets, while Verizon and Cablevision each led in one local market.

Business ISP Market Leaders by Business Size* in the Top 10 U.S. Local Markets
September 2011
Total U.S.
Source: comScore Business ISP Market Share Report
Local Markets All Businesses Large Businesses Small Businesses
ISP Share (%) of Internet Traffic ISP Share (%) of Internet Traffic ISP Share (%) of Internet Traffic
New York Verizon 20% Verizon 24% Cablevision 18%
Los Angeles AT&T 22% AT&T 27% AT&T 17%
Chicago AT&T 23% AT&T 29% Comcast 21%
Philadelphia AT&T 19% AT&T 32% Comcast 27%
San Francisco AT&T 20% Verizon 23% AT&T 23%
Boston Verizon 22% Verizon 36% Comcast 24%
Washington, DC Verizon 19% AT&T 28% Verizon 17%
Dallas AT&T 29% AT&T 34% AT&T 24%
Detroit AT&T 31% AT&T 37% Comcast 22%
Atlanta AT&T 30% AT&T 38% AT&T 25%

*Based on the number of employees per business

AT&T Drives Approximately 30 Percent of Financial Services and Healthcare Business Internet Traffic

An analysis of the business ISP leaders for different industries revealed AT&T drove approximately 30 percent of traffic in the Financial Services and Healthcare and Medical industries in September 2011, showing a notable lead over other ISPs. In contrast, the Telecommunications and Software and Technology industries showed greater market fragmentation among business ISPs, with the leading providers driving less than one-fifth of traffic in these markets, followed closely by their competitors. Verizon and CenturyLink/Qwest ranked among the top three business ISPs for several industries as well.

Top 3 Business ISPs for Selected Industries
September 2011
Total U.S.
Source: comScore Business ISP Market Share Report
ISP Share (%) of Internet Traffic
Financial Services
AT&T 30%
Verizon 24%
Level 3 9%
Healthcare & Medical
AT&T 31%
CenturyLink/Quest 10%
Verizon 9%
Software & Technology
AT&T 18%
Verizon 17%
CenturyLink/Q 13%
Internap Network Svcs. 11%
AT&T 11%

About comScore

comScore, Inc. (NASDAQ: SCOR) is a global leader in measuring the digital world and preferred source of digital business analytics. For more information, please visit

Carmela Aquino
comScore, Inc.