Martin Marietta Materials agreed to acquire limestone supplier Lhoist North America in a transaction valued at $13.5 billion, including debt, according to people familiar with the matter. The Raleigh, N.C.-based building-materials company will fund the purchase through $7 billion in cash and $6.5 billion in stock, with an announcement expected as soon as Monday morning.

This acquisition represents the largest deal in Martin Marietta's history, significantly expanding its footprint in the aggregates and specialty materials market. The company currently holds a market capitalization exceeding $36 billion, making it a major player in construction materials across North America.

Lhoist North America brings substantial limestone reserves and processing capabilities to the combined entity. The merger strengthens Martin Marietta's position in supplying essential raw materials for infrastructure projects and commercial construction, sectors that have shown resilience despite economic uncertainty.

The transaction signals continued consolidation in the construction materials sector as companies seek scale advantages. With infrastructure spending remaining a priority and housing demand steady, this deal positions Martin Marietta to capitalize on long-term growth trends in its core markets.