| MFMay Foundry & Machine CO | Slc | UT | — | ◇ UNVERIFIED |
| MMcwane | Tyler | TX | — | ◇ UNVERIFIED |
| MCMcwane Cast Iron Pipe CO. | Birmingham | AL | — | ◇ UNVERIFIED |
| MCMcwane Cast Iron Pipe CO. | Birmingham | AL | — | ◇ UNVERIFIED |
| MIMcwane, INC. | Oakland | CA | — | ◇ UNVERIFIED |
| MAMeltec a Div of Young CORP | Seattle | WA | — | ◇ UNVERIFIED |
| MRMerdian Rail Products CORP | Cicero | IL | — | ◇ UNVERIFIED |
| MSMetaldyne Sinterforged Products LLC | North Vernon | IN | — | ◇ UNVERIFIED |
| MPMetalico Pgh INC | Pittsburgh | PA | — | ◇ UNVERIFIED |
| MTMetal Technologies Dba Ravenna Ductile Iron Plant | Ravenna | MI | — | ◇ UNVERIFIED |
| MIMetaltek International, INC. | Pevely | MO | — | ◇ UNVERIFIED |
| MIMetaltek International, Sandusky International Division (0322020117) | Sandusky | OH | — | ◇ UNVERIFIED |
| MLMetavation LLC Vassar Plt | Vassar | MI | — | ◇ UNVERIFIED |
| MMMetso Minerals Industries INC | Birmingham | AL | — | ◇ UNVERIFIED |
| MOMetso Outotec USA INC | Warrenton | MO | — | ◇ UNVERIFIED |
| MSMichigan Steel, INC. | Muskegon | MI | — | ◇ UNVERIFIED |
| MMMicro Metals | Richmond | CA | — | ◇ UNVERIFIED |
| MAMidwest Alloys Foundry | O Fallon | MO | — | ◇ UNVERIFIED |
| MFMidwest Fabrication and Steel LLC | Pueblo | CO | — | ◇ UNVERIFIED |
| MMMidwest Metallurgical Laboratory INC | Marshall | MI | — | ◇ UNVERIFIED |
| MMMidwest Metallurgical Laboratory Site | Marshall | MI | — | ◇ UNVERIFIED |
| MFMike's Foundry INC. | Ravenna | MI | — | ◇ UNVERIFIED |
| MAMiller and Company LLC | Mulga | AL | — | ◇ UNVERIFIED |
| MUMimecri Usa, LLC | Thomasville | GA | — | ◇ UNVERIFIED |
| MFMission Foundry INC | Omaha | NE | — | ◇ UNVERIFIED |
| MPMississippi Precision Casting Parts, LLC | Columbus | MS | — | ◇ UNVERIFIED |
| MSMissouri Steel Castings Incorporated | Joplin | MO | — | ◇ UNVERIFIED |
 M&l Precision Machining INC | Morgan Hill | CA | — | ◇ UNVERIFIED |
| MNM & N Alloy Cast Products, INC. | Sylacauga | AL | — | ◇ UNVERIFIED |
| MPModern Pattern & Foundry CO. INC. (mp) | Vernon | CA | — | ◇ UNVERIFIED |
| MMMonett Metals Inc-monett Steel Castings | Monett | MO | — | ◇ UNVERIFIED |
| MCMonroe Custom Utility Bodies, INC. | Greenfield | IN | — | ◇ UNVERIFIED |
| MMMontague Machine CO | Montague (turners Falls) | MA | — | ◇ UNVERIFIED |
| MCMpg Casting Technologies | Kingsford | MI | — | ◇ UNVERIFIED |
| MCMunicipal Castings INC | Madison | MN | — | ◇ UNVERIFIED |
| MAMzd Acquisitions INC Dba Moz Designs INC | Oakland | CA | — | ◇ UNVERIFIED |
| NFNational Foundry and Mfg. INC. | Crane | TX | — | ◇ UNVERIFIED |
| NMNational Metal Abrasive Company | Wadsworth | OH | — | ◇ UNVERIFIED |
| NFNeenah Foundry CO - Plants 2 and 3 (w2179) | Neenah | WI | — | ◇ UNVERIFIED |
| NCNew Castings Incorporated | Spokane | WA | — | ◇ UNVERIFIED |
| NCNew Castle Foundry/new Castle | New Castle | PA | — | ◇ UNVERIFIED |
| NFNew Found Metals INC | Port Townsend | WA | — | ◇ UNVERIFIED |
| NHNew Haven Foundry | New Haven | MI | — | ◇ UNVERIFIED |
| NVNew Vermillion Iron Works, INC. | Hoopeston | IL | — | ◇ UNVERIFIED |
| NINorgren INC | Littleton | CO | — | ◇ UNVERIFIED |
| NANorth American Royalties INC. Wheland Automotive Industries | Chattanooga | TN | — | ◇ UNVERIFIED |
| NSNorthern Steel Castings INC | Wisconsin Rapids | WI | — | ◇ UNVERIFIED |
| NCNorthwest Castings | Seattle | WA | — | ◇ UNVERIFIED |
| NMNrb Metals LLC | Saint Charles | MN | — | ◇ UNVERIFIED |
 Oil City Iron Works INC | Corsicana | TX | — | ◇ UNVERIFIED |
