 M-b Companies INC | Chilton | WI | Machinery Manufacturing333000 | — | ◇ UNVERIFIED |
| M-b Companies INC | Chilton | WI | Machinery Manufacturing333111 | — | ◇ UNVERIFIED |
| MBMccann Barrel | Milwaukee | WI | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| MMMcc Manufacturing INC | Oak Creek | WI | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| MWMcc - Wisconsin LLC | Green Bay | WI | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| MIMcp INC | Milwaukee | WI | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| MIMenard INC Fleet North | Eau Claire | WI | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| MGMenards General Office-fd921 | Eau Claire | WI | Wood Product Manufacturing321990 | — | ◇ UNVERIFIED |
| MPMenasha Packaging Company - Promotional Print Solutions (pps) | Neenah | WI | Paper Manufacturing322212 | — | ◇ UNVERIFIED |
| MPMenasha Packaging, LLC - Green Lake Division | Green Lake | WI | Paper Manufacturing322211 | — | ◇ UNVERIFIED |
| MMMercury Marine - Plant 33 | Oshkosh | WI | Machinery Manufacturing333618 | — | ◇ UNVERIFIED |
| MGMerit Gear LLC | Antigo | WI | Machinery Manufacturing333131 | — | ◇ UNVERIFIED |
| MMeritor | Oshkosh | WI | Transportation Equipment Manufacturing336350 | — | ◇ UNVERIFIED |
| MIMerkle-korff Industries | Richland Center | WI | Electrical Equipment, Appliance & Component Manufacturing335312 | — | ◇ UNVERIFIED |
| MTMetal Technologies, Inc.-west Allis Duct | Milwaukee | WI | Primary Metal Manufacturing331510 | — | ◇ UNVERIFIED |
| MMMetso Minerals | Milwaukee | WI | Fabricated Metal Product Manufacturing332312 | — | ◇ UNVERIFIED |
| MBMetz Baking Company of Eau Claire | Eau Claire | WI | Food Manufacturing311812 | — | ◇ UNVERIFIED |
| MBMidwest Biofuel, LLC | Clinton | WI | Chemical Manufacturing325199 | — | ◇ UNVERIFIED |
| MPMilk Products, LLC | Chilton | WI | Food Manufacturing311514 | — | ◇ UNVERIFIED |
| MCMill Creek Cheese, LLC | Arena | WI | Food Manufacturing311513 | 20-99 | ◇ UNVERIFIED |
| MEMiller Electric - Light Industrial | Appleton | WI | Machinery Manufacturing333990 | — | ◇ UNVERIFIED |
| MEMiller Electric Manufacturing LLC - Ie North | Greenville | WI | Machinery Manufacturing333992 | — | ◇ UNVERIFIED |
| MPMilliporesigma - Port Washington | Port Washington | WI | Chemical Manufacturing325199 | — | ◇ UNVERIFIED |
| MIMilprint INC | Denmark | WI | Paper Manufacturing322221 | — | ◇ UNVERIFIED |
| MMMilsco Mfg CO | Milwaukee | WI | Transportation Equipment Manufacturing336360 | — | ◇ UNVERIFIED |
| MCMilwaukee County Transit System-flt Maint | Milwaukee | WI | Fabricated Metal Product Manufacturing332810 | — | ◇ UNVERIFIED |
| MGMilwaukee Gray Iron, LLC | West Allis | WI | Primary Metal Manufacturing331510 | — | ◇ UNVERIFIED |
 Milwaukee Valve CO INC | Milwaukee | WI | Fabricated Metal Product Manufacturing332910 | — | ◇ UNVERIFIED |
| MBMmc Bidding | New Berlin | WI | Computer and Electronic Product Manufacturing334000 | — | ◇ UNVERIFIED |
| MWMonarch Ware INC | Algoma | WI | Fabricated Metal Product Manufacturing332312 | — | ◇ UNVERIFIED |
| MFMondovi Foods Corporation/mondovi | Mondovi | WI | Food Manufacturing311514 | — | ◇ UNVERIFIED |
| MTMonopanel Technologies INC | West Allis | WI | Computer and Electronic Product Manufacturing334220 | — | ◇ UNVERIFIED |
| MTMonroe Truck Equipment | Janesville | WI | Transportation Equipment Manufacturing336211 | — | ◇ UNVERIFIED |
| MMMorris Material Handling INC | Oak Creek | WI | Machinery Manufacturing333923 | — | ◇ UNVERIFIED |
| MCMotor Castings CO | Milwaukee | WI | Primary Metal Manufacturing331510 | — | ◇ UNVERIFIED |
| MEMsi Express INC | Rosendale | WI | Food Manufacturing311411 | — | ◇ UNVERIFIED |
| NINafco International INC | Fond Du Lac | WI | Electrical Equipment, Appliance & Component Manufacturing335132 | — | ◇ UNVERIFIED |
| NLNagel Lumber CO INC | Land O Lakes | WI | Wood Product Manufacturing321110 | — | ◇ UNVERIFIED |
| NONatural Ovens Bakery | Manitowoc | WI | Food Manufacturing311811 | — | ◇ UNVERIFIED |
| NONatural Ovens of Manitowoc INC | Manitowoc | WI | Food Manufacturing311810 | — | ◇ UNVERIFIED |
| NCNcr Corporation - Viroqua | Viroqua | WI | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| NGNelson Global Products INC | Viroqua | WI | Transportation Equipment Manufacturing336390 | — | ◇ UNVERIFIED |
| NCNemschoff Chairs INC | Sheboygan | WI | Furniture and Related Product Manufacturing337120 | — | ◇ UNVERIFIED |
| NCNemschoff Chairs INC | Sheboygan | WI | Furniture and Related Product Manufacturing337120 | — | ◇ UNVERIFIED |
| NENeroco Engineering | Oconto | WI | Machinery Manufacturing333120 | — | ◇ UNVERIFIED |
| NPNestle Pizza Division | Medford | WI | Food Manufacturing311410 | — | ◇ UNVERIFIED |
| NPNexus Pharmaceuticals | Pleasant Prairie | WI | Chemical Manufacturing325410 | — | ◇ UNVERIFIED |
| NMNiagara Mill | Niagara | WI | Paper Manufacturing322110 | — | ◇ UNVERIFIED |
| NPNickelson Plastics INC | Osceola | WI | Fabricated Metal Product Manufacturing332999 | — | ◇ UNVERIFIED |
| NANorth American Pipe CORP | Janesville | WI | Plastics and Rubber Products Manufacturing326122 | — | ◇ UNVERIFIED |
