| JTJohnson Timber Corporation | Hayward | WI | Wood Product Manufacturing321110 | — | ◇ UNVERIFIED |
| JTJohnson Timber Corporation | Park Falls | WI | Wood Product Manufacturing321999 | — | ◇ UNVERIFIED |
| KIKage Innovations Corporation | Osceola | WI | Machinery Manufacturing333112 | 20-99 | ◇ UNVERIFIED |
| KIKerry INC | Rhinelander | WI | Food Manufacturing311942 | — | ◇ UNVERIFIED |
| KPKerwin Paper CO | Appleton | WI | Paper Manufacturing322120 | — | ◇ UNVERIFIED |
| KMKimberly Mill | Kimberly | WI | Paper Manufacturing322120 | — | ◇ UNVERIFIED |
| KLKitpackers LLC (former) | Germantown | WI | Chemical Manufacturing325520 | — | ◇ UNVERIFIED |
| KTKleen Test Products | Port Washington | WI | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
| KAKoenig and Vitts Mirro Plnt 5 | Manitowoc | WI | Primary Metal Manufacturing331314 | — | ◇ UNVERIFIED |
| KFKomatsu Forest LLC | Shawano | WI | Machinery Manufacturing333120 | — | ◇ UNVERIFIED |
| KKKono Kogs | Green Bay | WI | Machinery Manufacturing333413 | — | ◇ UNVERIFIED |
| KFKraft Foods Global, INC. | Beaver Dam | WI | Food Manufacturing311510 | — | ◇ UNVERIFIED |
| KFKraft Foods - Oscar Mayer | Madison | WI | Food Manufacturing311610 | — | ◇ UNVERIFIED |
| KIKramer International | Milwaukee | WI | Primary Metal Manufacturing331510 | — | ◇ UNVERIFIED |
| KIKrueger International | Manitowoc | WI | Furniture and Related Product Manufacturing337210 | — | ◇ UNVERIFIED |
| LCLa Crosse Footwear INC | La Crosse | WI | Leather and Allied Product Manufacturing316211 | — | ◇ UNVERIFIED |
| LCLake Country Foods. INC. | Oconomowoc | WI | Food Manufacturing311000 | — | ◇ UNVERIFIED |
| LSLakeland Sports Center | Plymouth | WI | Food Manufacturing311225 | — | ◇ UNVERIFIED |
| LSLakeland Sports Center, INC. | Greenbush | WI | Transportation Equipment Manufacturing336210 | — | ◇ UNVERIFIED |
 Lakeside Foods INC | Belgium | WI | Food Manufacturing311421 | — | ◇ UNVERIFIED |
| LFLakeside Foods INC - Eden | Eden | WI | Food Manufacturing311111 | — | ◇ UNVERIFIED |
| LPLaminated Products, INC. | Kenosha | WI | Food Manufacturing311320 | — | ◇ UNVERIFIED |
| LELeeson Electric CORP | Grafton | WI | Electrical Equipment, Appliance & Component Manufacturing335310 | — | ◇ UNVERIFIED |
| LELeeson Electric CORP | Saukville | WI | Electrical Equipment, Appliance & Component Manufacturing335310 | — | ◇ UNVERIFIED |
| LFLeick Furniture, INC. | Sheboygan | WI | Furniture and Related Product Manufacturing337120 | — | ◇ UNVERIFIED |
| LCLesaffreyeast CORP | Milwaukee | WI | Food Manufacturing311420 | — | ◇ UNVERIFIED |
| LMLeslie Marble Products INC | Thorp | WI | Chemical Manufacturing325991 | — | ◇ UNVERIFIED |
| LOLignetics of Great Lakes LLC | Hayward | WI | Wood Product Manufacturing321999 | — | ◇ UNVERIFIED |
| LPLitho Productions | Madison | WI | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| LLLoparex LLC | Hammond | WI | Paper Manufacturing322220 | — | ◇ UNVERIFIED |
 Louisiana Pacific Tomahawk Wi | Tomahawk | WI | Wood Product Manufacturing321219 | — | ◇ UNVERIFIED |
| LPL P I, INC. | Eau Claire | WI | Machinery Manufacturing333998 | — | ◇ UNVERIFIED |
| LLLubrizol Life Sciences INC | Franklin | WI | Plastics and Rubber Products Manufacturing326299 | — | ◇ UNVERIFIED |
| LMLucigen Middleton Wi | Middleton | WI | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
| LWL & W Construction | Markesan | WI | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| MMMacfab Metal Products | Beaver Dam | WI | Fabricated Metal Product Manufacturing332320 | — | ◇ UNVERIFIED |
| MPMadison Pre-hung Doors & Pre-finishing | Oregon | WI | Wood Product Manufacturing321918 | — | ◇ UNVERIFIED |
| MTMain Tape Company | Plymouth | WI | Paper Manufacturing322220 | — | ◇ UNVERIFIED |
| MCManitowoc Cranes | Port Washington | WI | Machinery Manufacturing333120 | — | ◇ UNVERIFIED |
| MIMaple Island INC | Medford | WI | Food Manufacturing311514 | — | ◇ UNVERIFIED |
| MIMarathon Industrial Finishing LLC | Marathon | WI | Chemical Manufacturing325510 | 1-19 | ◇ UNVERIFIED |
| MYMarquis Yachts Faclty 2nd | Pulaski | WI | Transportation Equipment Manufacturing336610 | — | ◇ UNVERIFIED |
| MYMarquis Yachts LLC - Facility 1 | Pulaski | WI | Transportation Equipment Manufacturing336612 | — | ◇ UNVERIFIED |
| MTMarshall Towne Millwork LLC Dba Auburn Ridge | Marshall | WI | Wood Product Manufacturing321910 | — | ◇ UNVERIFIED |
| MCMasonite CORP | Algoma | WI | Wood Product Manufacturing321911 | — | ◇ UNVERIFIED |
| MSMason Shoe Mfg Company | Chippewa Falls | WI | Leather and Allied Product Manufacturing316210 | — | ◇ UNVERIFIED |
| MIMathews INC | Sparta | WI | Miscellaneous Manufacturing339920 | — | ◇ UNVERIFIED |
| MPMatthews Paint CO | Pleasant Prairie | WI | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| MLMaysteel LLC - Mayville Division | Mayville | WI | Fabricated Metal Product Manufacturing332000 | — | ◇ UNVERIFIED |
| MEMayville Engineering Company INC | Neillsville | WI | Fabricated Metal Product Manufacturing332116 | — | ◇ UNVERIFIED |
