AT&T has signed a fiber supply agreement with Corning worth approximately $3 billion, extending a commercial relationship that stretches back more than four decades and underscoring the scale of the operator's ongoing fiber expansion in the United States.

The deal makes Corning a principal supplier of optical cable and related fiber components for AT&T's wireline network build. Corning, which invented low-loss optical fiber in 1970 and remains one of the world's largest producers of the material, has supplied AT&T since the earliest days of fiber deployment in the 1980s. The new contract ranks among the most significant supply agreements Corning has announced with a single carrier.

For AT&T, the agreement locks in supply capacity for a multi-year fiber construction program the operator has repeatedly identified as its principal capital priority. AT&T has been shifting investment away from legacy copper plant and toward fiber-to-the-home expansion, targeting both new neighborhoods and its existing wireline footprint. Long-term supply contracts of this kind give operators price visibility and guaranteed delivery volumes at a time when fiber and associated components have faced periodic capacity constraints.

The announcement also signals demand strength on the vendor side. Corning's optical communications segment has benefited as US carriers accelerate fiber builds, and a commitment of this size from the country's largest fiber builder provides a durable revenue base for the segment.

The financial terms call for roughly $3 billion in purchases over the life of the agreement, according to the announcement. Neither company disclosed a precise end date for the contract in the initial release.

AT&T's fiber push comes as US operators look to fixed broadband as a growth engine amid a maturing wireless market. The operator has set an ambition to reach tens of millions of fiber locations and has paired its own construction with commercial open-access arrangements. Securing components at scale is a precondition for hitting those coverage targets on schedule.

The agreement carries no disclosed conditions tied to government funding programs, but it aligns with the broader policy environment in Washington, where federal broadband initiatives continue to prioritize fiber infrastructure for underserved areas. Vendor contracts with anchor customers such as AT&T position suppliers like Corning to participate in that incremental demand as federally funded projects move from allocation to construction phases.

For Corning, the deal follows a period of heavy investment in US fiber manufacturing capacity, including expanded production at its facilities in North Carolina. Carrier commitments of this magnitude typically support that capacity expansion by guaranteeing offtake volumes.

AT&T expects the supply arrangement to support its fiber build plans through the second half of the decade, as the operator works to extend its fiber footprint across its service territory.