Martin Marietta Materials (MMM) is a rock star. The company is the #1 US producer (following its purchase of Texas Industries) of aggregates for highway, infrastructure, commercial, and residential construction. Its Martin Marietta Aggregates unit produces more than 125 million tons of granite, gravel, limestone, and sand annually. Aggregates represents nearly 85% of MMM's sales. The company's Magnesia Specialties unit produces magnesia-based chemicals for industrial, environmental, and agricultural uses, as well as fiber-reinforced composite materials for transportation and military applications. MMM was formed in 1993 from the quarries business of aerospace giant Martin Marietta Corp. (now Lockheed Martin).