Martin Marietta Materials Inc. (MLM)

Martin Marietta is a natural resource-based building materials company. It supplies aggregates, meaning crushed stone, sand and gravel, from a network of approximately 400 quarries, mines and distribution yards in 28 states, Canada and The Bahamas, and aggregates produced 88% of total reportable segment gross profit in 2025. It also sells cement, ready mixed concrete, asphalt and paving services in selected markets where it already holds an aggregates position, all reported together as the Building Materials business. A separate Specialties business makes magnesia-based products and dolomitic lime. It was formed in 1993 as a North Carolina corporation to succeed the materials group of what is now Lockheed Martin, listed part of its stock in 1994, became wholly public in 1996, and has completed over 100 acquisitions since.

Where the materials go

The heavy-side products go into infrastructure, nonresidential and residential construction, and aggregates are also used in agricultural, utility and environmental applications and as railroad ballast. In 2025, 37% of aggregates shipments went to highway and other public infrastructure projects, with the rest mainly to private nonresidential and residential work, a mix the filing states lessens the impact of swings in private-sector construction spending. The ten largest revenue-generating states, Texas, North Carolina, Colorado, California, Georgia, Florida, South Carolina, Arizona, Iowa and Minnesota, were 76% of Building Materials revenue from continuing operations.

Aggregates and how they move

Aggregates are an engineered granular material made to specific sizes, grades and chemistry. Operations are mostly open pit quarries, though the company is the largest operator of underground aggregates mines in the United States, with 13 active underground mines in the East Group. Because transport costs are high relative to the price of the product, truck shipments travel only so far from a quarry, and proximity to a customer's plant, a construction site or a long-haul corridor is a key competitive factor. Alongside trucks the company uses rail and waterborne networks, where per-mile costs are lower, to move material from domestic and offshore sources into markets where local supply is constrained.

Specialties

The Specialties business produces dolomitic lime at Woodville, Ohio and high-purity natural and synthetic magnesia-based products, including magnesium sulfate, magnesium oxide and magnesium hydroxide, at plants in Michigan, Ohio, Nevada, North Carolina, Indiana and Pennsylvania. Those products go into flame retardants, wastewater treatment, pulp and paper production and other specialty uses, while lime is sold mainly to the steel industry and for soil stabilisation, and is also used internally in synthetic magnesia production. In 2025 magnesia-based products were 67% of Specialties revenue, lime 32% and construction stone 1%. The principal raw materials are dolomitic limestone, magnesium-rich brine and magnesite, and reserves are described as sufficient to sustain current production for the foreseeable future.

Buying and selling operations

In January 2024 the company bought Albert Frei and Sons, an aggregates producer in Colorado, adding more than 60 years of hard rock reserves at current production levels around Denver. In February 2024 it sold its South Texas cement business and related concrete operations, including the Hunter cement plant and 20 concrete plants serving Austin and San Antonio, to a CRH subsidiary. In April 2024 it acquired 20 active aggregates operations in Alabama, South Carolina, South Florida, Tennessee and Virginia from Blue Water Industries affiliates, then aggregates assets in South Florida and Southern California in October 2024 and a bolt-on in West Texas that December. In July 2025 it bought Premier Magnesia, which the company states is the largest producer of natural magnesite and Epsom salt in the United States. In August 2025 it agreed an asset exchange with Quikrete, taking aggregates facilities producing approximately 20 million tons a year across Virginia, Missouri, Kansas and Vancouver plus cash, and giving up the Midlothian cement plant, cement terminals and Texas concrete assets, which are now held for sale and reported as discontinued operations.

Weather and people

The work is done outdoors, so precipitation, flooding, hurricanes, snowstorms, extreme temperatures, wildfires, earthquakes and droughts move production schedules, shipments and costs; winter weather bears on the first and fourth quarters, heavy rain and heat on the second and third. At 31 January 2026 the company had approximately 9,600 employees, approximately 7,100 of them hourly and 2,500 salaried, with approximately 1,200 hourly employees represented by labour unions.

From Martin Marietta's annual report on Form 10-K for the year ended 31 December 2025. The filing