| MCMadison Cable CORP | Worcester | MA | Primary Metal Manufacturing331422 | — | ◇ UNVERIFIED |
| MFMaeco Fabrication INC | Grand Bay | AL | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
 Magnetic Metals Corporation | Camden | NJ | Primary Metal Manufacturing331221 | — | ◇ UNVERIFIED |
| MCMag-tec Casting CORP | Jackson | MI | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
| MIMahle Inc-muskegon Hts Complex | Muskegon | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MBMaiden Bronze | Sandy | OR | Primary Metal Manufacturing331529 | — | ◇ UNVERIFIED |
| MMMandel Metals INC. | Franklin Park | IL | Primary Metal Manufacturing331312 | — | ◇ UNVERIFIED |
| MFMansfield Foundry Corporation | Mansfield | OH | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MBManufacturers Brass & Aluminum Fdry INC | Blue Island | IL | Primary Metal Manufacturing331525 | — | ◇ UNVERIFIED |
| MEMarathon Equipment CO | Fayette | AL | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
| MUMarcegaglia USA | Greenville | PA | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| MGMark Gray Enterprises | Columbus | OH | Primary Metal Manufacturing331314 | — | ◇ UNVERIFIED |
| MBMartin Brass Fndy | Torrance | CA | Primary Metal Manufacturing331525 | — | ◇ UNVERIFIED |
| MRMaryland Recycling | Baltimore | MD | Primary Metal Manufacturing331314 | — | ◇ UNVERIFIED |
| MSMaryland Specialty Wire | Cockeysville | MD | Primary Metal Manufacturing331111 | — | ◇ UNVERIFIED |
| MMMasonic Medical Research Lab | Utica | NY | Primary Metal Manufacturing331491 | — | ◇ UNVERIFIED |
| MHMaster Halco INC | Canton | MA | Primary Metal Manufacturing331222 | — | ◇ UNVERIFIED |
| MRMaterials Recovery Technologies | York | PA | Primary Metal Manufacturing331492 | — | ◇ UNVERIFIED |
| MTMaterials Technology INC | Somerset | NJ | Primary Metal Manufacturing331421 | — | ◇ UNVERIFIED |
 Matthews International CORP | Seneca Falls | NY | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
| Matthews International CORP | Romoland | CA | Primary Metal Manufacturing331525 | — | ◇ UNVERIFIED |
| Matthews International Corporation | Kingwood | WV | Primary Metal Manufacturing331525 | — | ◇ UNVERIFIED |
| MTMaverick Tube Corporation | Ferndale | MI | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| MCMax Cast | Kalona | IA | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| MCMax Casting Co-benton Harbor | Benton Harbor | MI | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
| MSMaya Steel Fabrications INC | Gardena | CA | Primary Metal Manufacturing331111 | — | ◇ UNVERIFIED |
| MIM-b Industries Wwtp | Rosman | NC | Primary Metal Manufacturing331222 | — | ◇ UNVERIFIED |
| MGMccoy Global USA | Broussard | LA | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| MMMcgraw Manufacturing INC | Anaheim | CA | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| MSMclouth Steel Gibraltar Plant | Gibraltar | MI | Primary Metal Manufacturing331221 | — | ◇ UNVERIFIED |
| MCMcwane Cast Iron Pipe CO. | Birmingham | AL | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MMepco | Marshalltown | IA | Primary Metal Manufacturing331528 | — | ◇ UNVERIFIED |
| MRMercury Refining CO INC | Albany | NY | Primary Metal Manufacturing331000 | — | ◇ UNVERIFIED |
| MTMercury Tube - 3211 W Bear Creek Dr | Englewood | CO | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| MPMeridian Pr0ducts of America | Eaton Rapids | MI | Primary Metal Manufacturing331523 | — | ◇ UNVERIFIED |
| MBMetal Bank of America | Philadelphia | PA | Primary Metal Manufacturing331420 | — | ◇ UNVERIFIED |
 Metal Culverts INC Florida Div | Clearwater | FL | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| Metal Culverts INC M & M Highway Materials Div | Columbia | MO | Primary Metal Manufacturing331221 | — | ◇ UNVERIFIED |
| MMetaldyne | Niles | IL | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
| MSMetaldyne Sintered Ridgway LLC | Emporium | PA | Primary Metal Manufacturing331110 | — | ◇ UNVERIFIED |
| MCMetalloy Corp, The, Mississippi Division | Shannon | MS | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| MMMetal Management Midwest INC | Kankakee | IL | Primary Metal Manufacturing331423 | — | ◇ UNVERIFIED |
| MEMetalor Electrotechnics USA Corp/plt 5 | Delmont | PA | Primary Metal Manufacturing331491 | — | ◇ UNVERIFIED |
| MSMetal Separations INC | Nashua | NH | Primary Metal Manufacturing331492 | — | ◇ UNVERIFIED |
| MIMetals Investment Trust LTD. | East Chicago | IN | Primary Metal Manufacturing331492 | — | ◇ UNVERIFIED |
| MSMetal Source LLC | Wabash | IN | Primary Metal Manufacturing331492 | — | ◇ UNVERIFIED |
| MTMetal Technologies, Inc.-west Allis Duct | Milwaukee | WI | Primary Metal Manufacturing331510 | — | ◇ UNVERIFIED |
| MIMetaltek International Southern Centrifugal Div | Chattanooga | TN | Primary Metal Manufacturing331525 | — | ◇ UNVERIFIED |
| MFMet-a-lum Fabricators | Paramount | CA | Primary Metal Manufacturing331315 | — | ◇ UNVERIFIED |
| MSMetrock Steel & Wire CO. | Montevallo | AL | Primary Metal Manufacturing331222 | — | ◇ UNVERIFIED |
