21 May U.S. Fiber Lit Buildings to Exceed 2 Million in 2026
May 21, 2026
By Rosemary Cochran
Principal & Co-Founder, Vertical Systems Group
Vertical Systems Group’s latest research indicates that U.S. fiber lit buildings will surpass 2 million sites in 2026. Leading providers are actively installing ultra-high capacity, low latency fiber connectivity to support AI workloads, cybersecurity services, edge computing and other essential applications.
U.S. Fiber Availability
2025 U.S. Fiber Availability research includes more than 5 million commercial buildings and data centers. These sites extend to greater than 7 million commercial establishments where business is conducted, goods are made or processed, or services are rendered.
- As shown in the chart, 36% of U.S. commercial buildings and data centers were fiber lit as of year-end 2025.
- The chart also shows that the percent of lit buildings in the Fiber 20+ employees segment far exceeds the percent of lit buildings in the Fiber <20 employees segment.
- Most U.S. fiber lit commercial buildings are currently served by a single provider. This is evolving as fiber network diversity becomes more essential for business customers.
- Challenges to new fiber deployments involve high costs for construction, obtaining access rights from property owners and the right of way for construction.
- Fiber investments will continue to be impacted by ongoing M&A activity and federal funding grants.
Top U.S. Fiber Providers
Vertical Systems Group’s 2025 U.S. Fiber Lit Buildings LEADERBOARD results include thirteen companies (in rank order, based on 25,000 or more on-net fiber lit buildings and data centers): AT&T, Verizon, Spectrum Business, Comcast Business, Lumen, Cox Business, Zayo, Crown Castle, Frontier, Uniti, Breezeline, Brightspeed and Segra.
Seven companies attained a 2025 Challenge Tier citation as follows (in alphabetical order, based on between 5,000 and 24,999 U.S. fiber lit commercial sites): Altafiber, Conterra Networks, Everstream, Fidium, FirstLight, Great Plains Communications, and Lightpath.
Fiber Outlook
Fiber lit buildings and data centers are strategic assets. Lit buildings enable delivery of network services faster and more readily, without construction costs and extensive lead times required to install new fiber. Currently numerous billion-dollar investments in new U.S. data centers are in process or planned, adding to the thousands already operational. Investors aim to construct newer facilities that can accommodate immense AI workloads.
Optical fiber is essential for AI. High-capacity, low-latency lit fiber enables the utilization of AI for massive computing between processors and data centers, as well as faster transfer of datasets. Consequently, many larger AI data facilities now require 10 times more fiber than traditional data centers.
Wavelength demand is escalating fiber requirements. Top wavelength providers cite that customer demand for 400 Gbps fiber services is accelerating. Heavy AI workloads are boosting demand for Wavelength services up to 800 Gbps and 1.6 Tbps. Wavelength customers include hyperscalers, AI and GenAI companies, data centers and large enterprises.
@Fiber is available now exclusively by subscription to an ENS Research Program. Research data includes in-depth quantification of the U.S. fiber market plus lit building counts by service provider that power the Fiber Lit Buildings LEADERBOARD rankings. Contact us for more information and pricing.
Source: ENS Research Program excerpts from @Fiber and @Wavelength.