| MCMaggie Chacon | El Paso | TX | — | ◇ UNVERIFIED |
| MSMagni-fab Southwest Company, INC. | Howe | TX | — | ◇ UNVERIFIED |
| MSMain Street Fabrications and Manufacturing, LLC | Brooksville | FL | — | ◇ UNVERIFIED |
| MMMaintenance & Machinery Erectors, INC. | Mulberry | FL | — | ◇ UNVERIFIED |
| MWMajestic Water Spouts, LLC | Mesa | AZ | — | ◇ UNVERIFIED |
| MSMammoth Solutions, LLC | Houston | TX | — | ◇ UNVERIFIED |
| MFMann's Fabrication & Welding Inc. | Columbus | OH | — | ◇ UNVERIFIED |
| MGManpower Group | Amarillo | TX | — | ◇ UNVERIFIED |
| MMMansfield Metal Solutions LLC | Ontario | CA | — | ◇ UNVERIFIED |
| MWMansfield Welding Services LLC | Oakwood | OH | — | ◇ UNVERIFIED |
| MIManufab, INC. | Bay Saint Louis | MS | — | ◇ UNVERIFIED |
| MLManufab, LLC | Rexburg | ID | — | ◇ UNVERIFIED |
| MWManz Work, INC. | Orlando | FL | — | ◇ UNVERIFIED |
| MFMarine Fab & Repair, INC | Houma | LA | — | ◇ UNVERIFIED |
| MBMark Body Truck & Equipment CO | Imlay City | MI | — | ◇ UNVERIFIED |
| MGMark Godfrey Sr Individual Dba United Iron Works | Orland | CA | — | ◇ UNVERIFIED |
| MKMark Knoedler | Ijamsville | MD | — | ◇ UNVERIFIED |
| MMMarkle Manufacturing Company of San Antonio | San Antonio | TX | — | ◇ UNVERIFIED |
| MMMarks Metal Technology INC | Clackamas | OR | — | ◇ UNVERIFIED |
| MSMark Steel CORP | Salt Lake City | UT | — | ◇ UNVERIFIED |
| MWMarks Welding & Fabricating | Thorsby | AL | — | ◇ UNVERIFIED |
| MLMarrick LLC | Norfolk | VA | — | ◇ UNVERIFIED |
| MIMarson International LLC | Elkhart | IN | — | ◇ UNVERIFIED |
| MIMarson International LLC | Elkhart | IN | — | ◇ UNVERIFIED |
| MIMarstrand Industries, INC. | Pittsburgh | PA | — | ◇ UNVERIFIED |
| MMMartelli's Metal Fabrication INC | Ivyland | PA | — | ◇ UNVERIFIED |
| MSMartha S Materials INC | Lexington | KY | — | ◇ UNVERIFIED |
| MSMartinez Steel | San Francisco | CA | — | ◇ UNVERIFIED |
| MIMartin Iron Works, INC | Reno | NV | — | ◇ UNVERIFIED |
| MIMartin Iron Works, INC. | Reno | NV | — | ◇ UNVERIFIED |
| MMMartin Manufactuirng, INC. | Sapulpa | OK | — | ◇ UNVERIFIED |
| MHMartin-Pittman Holdings, Inc. | Indianapolis | IN | — | ◇ UNVERIFIED |
| MSMartin Steel Constructors | Eleele | HI | — | ◇ UNVERIFIED |
| MWMartin Welding and Fabrication LLC | Contoocook | NH | — | ◇ UNVERIFIED |
| MSMaryland Structural Fabricators INC | Millington | MD | — | ◇ UNVERIFIED |
| MLMascoat LLC | West Monroe | LA | — | ◇ UNVERIFIED |
| MSMason Structural Steel INC. | Walton Hills | OH | — | ◇ UNVERIFIED |
| MWMason West, INC | Placentia | CA | — | ◇ UNVERIFIED |
| MWMaspeth Welding, INC | New York | NY | — | ◇ UNVERIFIED |
| MMMass Machine & Fabricating Company | Washington | PA | — | ◇ UNVERIFIED |
| MFMaster Flo Valve Usa, INC. | Houston | TX | — | ◇ UNVERIFIED |
| MVMatchless Valve Company | Marshall | MI | — | ◇ UNVERIFIED |
| MMMatcor Metal Fabrication | Morton | IL | — | ◇ UNVERIFIED |
| MCMaterial Control Systems, INC. | Cordova | IL | — | ◇ UNVERIFIED |
| MHMaterial Handling Technologies, INC. | North Syracuse | NY | — | ◇ UNVERIFIED |
| MIMattessich Iron, LLC | Baldwinsville | NY | — | ◇ UNVERIFIED |
| MIMattessich Iron, LLC | Memphis | NY | — | ◇ UNVERIFIED |
| MBMaura Buildings, Incorporated | Lebanon | PA | — | ◇ UNVERIFIED |
| MMMaurice Mesple Dba Mesples Machine Shop and Pump | Fresno | CA | — | ◇ UNVERIFIED |
| MSMay Specialty Fabricators, INC. | Register | GA | — | ◇ UNVERIFIED |
 Mayville Engineering Company INC Dba Mec | Vanderbilt | MI | — | ◇ UNVERIFIED |
| MEMbm Enterprises, INC. | Pleasant Plains | AR | — | ◇ UNVERIFIED |
| MWMcbrides Welding Dba American Iron | Ridgecrest | CA | — | ◇ UNVERIFIED |
| MMMcdonough Marine Service | Metairie | LA | — | ◇ UNVERIFIED |
| MMMcelroy Metal Mill INC | Monroe | LA | — | ◇ UNVERIFIED |
| MMMcelroy Metal Mill INC Dba Mcelroy Metal | Adelanto | CA | — | ◇ UNVERIFIED |
| MMMcfarlane Mfg CO | Sauk City | WI | — | ◇ UNVERIFIED |
| MHMckee Holdings LLC | Sandy | OR | — | ◇ UNVERIFIED |
| MFMcm Fabricators, INC. Dba Global Fabricators | Shafter | CA | — | ◇ UNVERIFIED |
| MCMcnichols Company | Garland | TX | — | ◇ UNVERIFIED |
| MIMcReynolds Investments LLC | Waterford | WI | — | ◇ UNVERIFIED |
| MCMDI Corporation | Cheney | KS | — | ◇ UNVERIFIED |
| MCMDI Corporation | Cheney | KS | — | ◇ UNVERIFIED |
| MWM-d Welding LLC | Minneapolis | MN | — | ◇ UNVERIFIED |
 Meadow-burke Products | Hazleton | PA | — | ◇ UNVERIFIED |
| MAMechanical and Industrial Steel Services, INC. | Channahon | IL | — | ◇ UNVERIFIED |
| MMMedia Metals, LLC | Jackson | TN | — | ◇ UNVERIFIED |
| MHMedway Hall Development Group, Inc. | Jacksonville | FL | — | ◇ UNVERIFIED |
| MPMellies Products INC. | Morganville | KS | — | ◇ UNVERIFIED |
| MSMemphis Sheet Metal Works INC | Memphis | TN | — | ◇ UNVERIFIED |
| MMMenard Manufacturing INC. | Dewitt | AR | — | ◇ UNVERIFIED |
| MMMenator Metal Works LLC | Winneconne | WI | — | ◇ UNVERIFIED |
| MMMequon Metals and Repair LLC | Mequon | WI | — | ◇ UNVERIFIED |
| MCMere Capital, LLC dba Czar Weld | House Springs | MO | — | ◇ UNVERIFIED |
| MSMeridian Specialty Vehicles | Las Vegas | NV | — | ◇ UNVERIFIED |
| MEMerrill Engineering & Integration | Saginaw | MI | — | ◇ UNVERIFIED |
| MFMerrill Fab | Merrill | WI | — | ◇ UNVERIFIED |
| MIMerrill Iron & Steel South | Springfield | MO | — | ◇ UNVERIFIED |
| MSMerrill Steel Camanche | Camanche | IA | — | ◇ UNVERIFIED |
| MVMesilla Valley Metals | Las Cruces | NM | — | ◇ UNVERIFIED |
| MMMesser Machine - Mfg INC | Windom | MN | — | ◇ UNVERIFIED |
| MLMetalbuilt LLC | Macomb | MI | — | ◇ UNVERIFIED |
| MIMetal-con, INC. | Sylvania | GA | — | ◇ UNVERIFIED |
| MCMetal Container Corporation | Oklahoma City | OK | — | ◇ UNVERIFIED |
| MLMetalCraft LLC | Bantam | CT | — | ◇ UNVERIFIED |
| MDMetal Design Corporation | Madison | WI | — | ◇ UNVERIFIED |
| MEMetal Enterprises, INC. | Portland | OR | — | ◇ UNVERIFIED |
| MAMetalfab Arizona L.l.c. | Phoenix | AZ | — | ◇ UNVERIFIED |
| MIMetalfab INC | Kennewick | WA | — | ◇ UNVERIFIED |
| MIMetalfab INC | Richland | WA | — | ◇ UNVERIFIED |
| MFMetal Fabrication INC | Winchester | TN | — | ◇ UNVERIFIED |
| MFMetal Fabrication Technologies D/b/a Gerdau Ameris | Johnson City | TN | — | ◇ UNVERIFIED |
| MFMetal Fabricators, LLC | Tallahassee | FL | — | ◇ UNVERIFIED |
| MFMetal Fabricators of St Louis | Saint Louis | MO | — | ◇ UNVERIFIED |
| MFMetal for Electronics LLC | Memphis | TN | — | ◇ UNVERIFIED |
| MKMetal Kings | Lynwood | CA | — | ◇ UNVERIFIED |
| MRMetalmade Raingutter & Sheetmetal INC | Irvine | CA | — | ◇ UNVERIFIED |
| MMMetal Magic, LLC | Ocala | FL | — | ◇ UNVERIFIED |
 Metal Master LLC | Tacoma | WA | — | ◇ UNVERIFIED |
| MMMetal Masters, INC. | Mitchellville | IA | — | ◇ UNVERIFIED |
