Kurita America INC | Brooklyn Park | MN | 500+ | ◐ LIKELY ACTIVE |
| LILabchem INC | Zelienople | PA | — | ◐ LIKELY ACTIVE |
| LNLafarge North America INC Andover Ready Mix | Andover | KS | — | ◐ LIKELY ACTIVE |
| LPLake Placid Cbp | Lake Placid | FL | — | ◐ LIKELY ACTIVE |
| LCLakes Concrete Plus | Bemidji | MN | 20–99 | ◐ LIKELY ACTIVE |
| LRLakeside Ready Mix INC. - Plant No 1 | Abingdon | VA | — | ◐ LIKELY ACTIVE |
| LRLakeside Ready Mix INC - Plant No 2 | Marion | VA | — | ◐ LIKELY ACTIVE |
| LRLawrence Redi Mix | Bridgewater | MA | — | ◐ LIKELY ACTIVE |
| LPLbv Prof Svc Llc/montoursville Boro Crem | Montoursville | PA | — | ◐ LIKELY ACTIVE |
| LSLigonier Stone & Lime Concrete | Latrobe | PA | 1–19 | ◐ LIKELY ACTIVE |
| LCLincoln CO Ready Mix INC | Stanford | KY | — | ◐ LIKELY ACTIVE |
| LRLincoln Ready-mix Concrete | Lincoln | MO | — | ◐ LIKELY ACTIVE |
| LPLindsay Precast INC. | Franklinton | NC | 20–99 | ◐ LIKELY ACTIVE |
| LPLindsay Precast SC | Rock Hill | SC | 20–99 | ◐ LIKELY ACTIVE |
| LSLithia Springs Plant 210 | Lithia Springs | GA | 20–99 | ◐ LIKELY ACTIVE |
| LOLive Oak Ready Mix, LLC | Ingleside | TX | 20–99 | ◐ LIKELY ACTIVE |
| LALombard Architectural Precast Products Company | Alsip | IL | 20–99 | ◐ LIKELY ACTIVE |
| LWLone Wolf Enterprises-harrisonville | Harrisonville | MO | — | ◐ LIKELY ACTIVE |
| LRLoughman Ready Mix Plant, Maschmeyer Concrete | Davenport | FL | — | ◐ LIKELY ACTIVE |
| LPLowe Precast, INC. | Waco | TX | — | ◐ LIKELY ACTIVE |
| LCL.s. Construction Services (was Licausi) | Independence | MO | — | ◐ LIKELY ACTIVE |
| LILycon INC | Janesville | WI | 100–499 | ◐ LIKELY ACTIVE |
| LRLynchburg Ready-mix Concrete CO INC | Lynchburg | VA | — | ◐ LIKELY ACTIVE |
| LRLynchburg Ready Mix Concrete CO INC - Appomattox | Appomattox | VA | — | ◐ LIKELY ACTIVE |
| MCMabank Cbp No 1 | Mabank | TX | — | ◐ LIKELY ACTIVE |
| MSMacdermid Specialty Chemical Services | Waterbury | CT | — | ◐ LIKELY ACTIVE |
Mack Industries of Bluffton | Bluffton | OH | 1–19 | ◐ LIKELY ACTIVE |
| MIMagsphere, INC. | Pasadena | CA | — | ▲ REPORTED CLOSED |
| MCMajor Concrete 2 New Kings Road Facility | Jacksonville | FL | — | ◐ LIKELY ACTIVE |
| MCMarion CO Concrete | Lebanon | KY | — | ◐ LIKELY ACTIVE |
| MRMarshallton Research Laboratories, INC. | Tobaccoville | NC | — | ▲ REPORTED CLOSED |
| MPMaryland Portable Concrete Elkton | Elkton | MD | 20–99 | ◐ LIKELY ACTIVE |
| MPMaryland Portable Concrete, INC. | Havre De Grace | MD | — | ◐ LIKELY ACTIVE |
| MCMaschmeyer Concrete/brooks Street Facility | Lakeland | FL | — | ◐ LIKELY ACTIVE |
| MCMaschmeyer Concrete-hickory Tree Rd | Saint Cloud | FL | — | ◐ LIKELY ACTIVE |
| MCMaschmeyer Concrete Rocket Blvd Facility | Orlando | FL | — | ◐ LIKELY ACTIVE |
| MBMaster Builder Solutions | Ashland | VA | — | ◐ LIKELY ACTIVE |
| MMMaster Made Tanks, Inc. | Paris | AR | 20–99 | ◐ LIKELY ACTIVE |
| MCMechanicsville Concrete Llc-petersburg Plant | Petersburg | VA | — | ◐ LIKELY ACTIVE |
| MIMecs INC | Martinez | CA | 20–99 | ◐ LIKELY ACTIVE |
| MMMemorial Monuments Meridian | Meridian | ID | 20–99 | ◐ LIKELY ACTIVE |
| MCMesquite Concrete Cuero | Cuero | TX | 1–19 | ◐ LIKELY ACTIVE |
| MCMetalube Coating | Corona | CA | 1–19 | ◐ LIKELY ACTIVE |
| MMMetromont Materials Corporation - Monroe Plant | Monroe | NC | — | ◐ LIKELY ACTIVE |
| MRMetro Ready Mix Concrete INC. | Nashville | TN | — | ◐ LIKELY ACTIVE |
| MRMetro Ready Mix & Supply Castor Ave Fac | Philadelphia | PA | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply | Henderson | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply - Eddyville Plant | Eddyville | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply INC - Morganfield | Morganfield | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply – Owensboro Plant | Owensboro | KY | — | ◐ LIKELY ACTIVE |