| MAManhole Adjusting Contractors | Monterey Park | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MMMarcellus Metalcasters INC | Marcellus | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MIMas Iron CO | Los Angeles | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MFMay Foundry & Machine CO | Slc | UT | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MMcwane | Tyler | TX | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MCMcwane Cast Iron Pipe CO. | Birmingham | AL | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MTMetal Technologies Dba Ravenna Ductile Iron Plant | Ravenna | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MLMetavation LLC Vassar Plt | Vassar | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MMMicro Metals | Richmond | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MMMidwest Metallurgical Laboratory INC | Marshall | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
 M&l Precision Machining INC | Morgan Hill | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MCMonroe Custom Utility Bodies, INC. | Greenfield | IN | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| MAMzd Acquisitions INC Dba Moz Designs INC | Oakland | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| NCNew Castings Incorporated | Spokane | WA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| NVNew Vermillion Iron Works, INC. | Hoopeston | IL | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| NSNorthern Steel Castings INC | Wisconsin Rapids | WI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| OCOneida Casting Group | Oneida | NY | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| OBOsc Builders | Pacific | MO | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| PHPacific Handy Cutter INC | Irvine | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| PSPacific Securities INC | Spokane | WA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| PMPadnos Manufacturing INC | Grand Rapids | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| PEParamount Extrusions CO. | Paramount | CA | Primary Metal Manufacturing331318 | — | ◇ UNVERIFIED |
| PFParhen Foundry, INC. | Amory | MS | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| PDPeter Day | Portland | OR | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| PCPrecision Cast Products | Oakland | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RIRansom Ind Lp/macungie | Macungie | PA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RPRayonier Performance Fibers LLC Marketing & Research Center | Jesup | GA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RMRenaissance Manufacturing Group, LLC | Waukesha | WI | Primary Metal Manufacturing331000 | — | ▲ REPORTED CLOSED |
| RCRichland Ctr Foundry CO (former) | Richland Center | WI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RFRidge Foundry INC | San Leandro | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RMR M Masonry | Richmond | VA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RCRockbridge Castings | Rockbridge | IL | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| RCRoss Cast Metals | Lancaster | OH | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SCSanders CO INC | Elizabeth City | NC | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SMSather Mfg CO INC | Everett | WA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SFSchwarb Foundry | Warren | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SISchwarb Industries INC | Troy | MI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SBSequoia Brick | Lindsay | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SBService Brass & Aluminum Foundry, INC. | Wichita | KS | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SESewer Equipment CO. of Florida, INC. | New Smyrna Beach | FL | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SFShelco Foundries Div of Gnutti Cado USA | Jacksonville | AL | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SMSimonz Machine Dba Hyve Technologies | San Diego | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SHSlack Horner Foundry | Longmont | CO | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SMSlinger Manufacturing CO INC | Slinger | WI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SMSlinger Mfg CO INC Plant 1 | Slinger | WI | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SSSo Safe Equipment | Motley | MN | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SFSpanish Fork Metals | Spanish Fork | UT | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
 Stang Industries INC | Corona | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| STStreuter Technologies INC | San Clemente | CA | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
| SMSupervac Manuf. | Broomfield | CO | Primary Metal Manufacturing331511 | — | ◇ UNVERIFIED |
