| LILufkin Industries INC | Lufkin | TX | Primary Metal Manufacturing331511 | 20-99 | ◐ LIKELY ACTIVE |
| MCMadison-kipp Corporation | Richmond | IN | Primary Metal Manufacturing331523 | 20-99 | ◐ LIKELY ACTIVE |
| MMMagnolia Metal CORP | Auburn | NE | Primary Metal Manufacturing331523 | 20-99 | ◐ LIKELY ACTIVE |
| MMMagnolia Metal & Plastic Products, INC | Vicksburg | MS | Plastics and Rubber Products Manufacturing326199 | 1-19 | ◐ LIKELY ACTIVE |
| MBMahle Behr Mt Sterling INC | Mount Sterling | OH | Primary Metal Manufacturing331318 | 100-499 | ◐ LIKELY ACTIVE |
| MFMahoney Foundries | Kendallville | IN | Primary Metal Manufacturing331524 | 100-499 | ◐ LIKELY ACTIVE |
| MGManitowoc Grey Iron Foundry INC | Manitowoc | WI | Primary Metal Manufacturing331511 | 1-19 | ◐ LIKELY ACTIVE |
| MUMarmon Utility LLC | Milford | NH | Primary Metal Manufacturing331318 | 100-499 | ◐ LIKELY ACTIVE |
| MSMatalco Shelbyville LLC | Shelbyville | KY | Primary Metal Manufacturing331314 | 100-499 | ◐ LIKELY ACTIVE |
| MBMaterion Brewster LLC | Brewster | NY | Primary Metal Manufacturing331491 | 20-99 | ◐ LIKELY ACTIVE |
| MBMaterion Brush INC | Lorain | OH | Primary Metal Manufacturing331314 | 20-99 | ◐ LIKELY ACTIVE |
| MTMaverick Tube | Conroe | TX | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
| MBMeskan Brass Foundry | Chicago | IL | Primary Metal Manufacturing331524 | 20-99 | ◐ LIKELY ACTIVE |
| MRMetallix Refining INC. | Greenville | NC | Primary Metal Manufacturing331314 | 20-99 | ◐ LIKELY ACTIVE |
| MIMetaltek Intl - Wisconsin Investcast | Watertown | WI | Primary Metal Manufacturing331510 | 100-499 | ◐ LIKELY ACTIVE |
| MIMetco Ind | Saint Marys | PA | Primary Metal Manufacturing331110 | 100-499 | ◐ LIKELY ACTIVE |
| MWMichigan Wheel CORP | Grand Rapids | MI | Primary Metal Manufacturing331525 | 20-99 | ◐ LIKELY ACTIVE |
| MAMid American Steel and Wire CO - Mill | Madill | OK | Primary Metal Manufacturing331110 | 100-499 | ◐ LIKELY ACTIVE |
| MMMidland Manufacturing CO. | Fort Worth | TX | Primary Metal Manufacturing331525 | 20-99 | ◐ LIKELY ACTIVE |
Midwest Metal Products INC | Winona | MN | Primary Metal Manufacturing331511 | 20-99 | ◐ LIKELY ACTIVE |
| MPMills Products, INC. | Athens | TN | Primary Metal Manufacturing331221 | 100-499 | ◐ LIKELY ACTIVE |
| MCMnp CORP | Utica | MI | Primary Metal Manufacturing331222 | 100-499 | ◐ LIKELY ACTIVE |
| MMMonett Metals INC | Monett | MO | Primary Metal Manufacturing331513 | 20-99 | ◐ LIKELY ACTIVE |
| MPMontana Precision Products LLC | Butte | MT | Primary Metal Manufacturing331512 | 100-499 | ◐ LIKELY ACTIVE |
| MBMorrison Brothers Company | Dubuque | IA | Primary Metal Manufacturing331524 | 1-19 | ◐ LIKELY ACTIVE |
| MIMost INC | Troy | MO | Primary Metal Manufacturing331314 | 20-99 | ◐ LIKELY ACTIVE |
| MFMueller Fittings CO INC | Covington | TN | Primary Metal Manufacturing331420 | 20-99 | ◐ LIKELY ACTIVE |
| MCMulti-cast CORP | Wauseon | OH | Primary Metal Manufacturing331521 | 20-99 | ◐ LIKELY ACTIVE |
| NUNemak USA INC | Glasgow | KY | Primary Metal Manufacturing331521 | 100-499 | ◐ LIKELY ACTIVE |
| NENew England Union Co., INC. | West Warwick | RI | Primary Metal Manufacturing331528 | 20-99 | ◐ LIKELY ACTIVE |
| NANorth American Hydraulic Excavation Facility | Victoria | TX | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
| NVNorth Vernon Industry CORP | North Vernon | IN | Primary Metal Manufacturing331511 | 100-499 | ◐ LIKELY ACTIVE |
| NPNorthwest Pipe CO | Adelanto | CA | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
| NPNtk Precision Axle CORP | Frankfort | IN | Primary Metal Manufacturing331221 | 100-499 | ◐ LIKELY ACTIVE |
| NSNucor Steel | Norfolk | NE | Primary Metal Manufacturing331110 | 500+ | ◐ LIKELY ACTIVE |
| NSNucor Steel Connecticut, INC. | Wallingford | CT | Primary Metal Manufacturing331110 | 20-99 | ◐ LIKELY ACTIVE |
| NSNucor Steel Kingman LLC | Kingman | AZ | Primary Metal Manufacturing331110 | 100-499 | ◐ LIKELY ACTIVE |
| NTNucor Tubular Products INC | Decatur | AL | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
Nyrstar Clarksville INC. | Clarksville | TN | Chemical Manufacturing325188 | — | ◐ LIKELY ACTIVE |
| OFO'hare Foundry Corporation | Maplewood | MO | Primary Metal Manufacturing331523 | 20-99 | ◐ LIKELY ACTIVE |
| OOOrchid Orthopedic Solutions Oregon, INC | Oregon City | OR | Primary Metal Manufacturing331512 | — | ◐ LIKELY ACTIVE |
| PIPace Industries - Cambridge Div | North Billerica | MA | Primary Metal Manufacturing331521 | 100-499 | ◐ LIKELY ACTIVE |
| PSPcc Schlosser | Redmond | OR | Primary Metal Manufacturing331512 | 100-499 | ◐ LIKELY ACTIVE |
| PSPcc Structurals | Carson City | NV | Primary Metal Manufacturing331512 | 100-499 | ◐ LIKELY ACTIVE |
| PAPermalok - a Northwest Pipe CO | Saint Louis | MO | Primary Metal Manufacturing331210 | 1-19 | ◐ LIKELY ACTIVE |
| PTPhoenix Tube CO | Bethlehem | PA | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
| PTPlymouth Tube Company | East Troy | WI | Primary Metal Manufacturing331210 | 20-99 | ◐ LIKELY ACTIVE |
Precision Casting Prototypes and Engineering INC | Commerce City | CO | Primary Metal Manufacturing331522 | — | ◐ LIKELY ACTIVE |
| PAPremier Aluminum INC | Racine | WI | Primary Metal Manufacturing331521 | 20-99 | ◐ LIKELY ACTIVE |
| PCPrysmian Cables & Systems USA | Paragould | AR | Primary Metal Manufacturing331420 | 100-499 | ◐ LIKELY ACTIVE |