| AGAmerican Generator & Armature CO | Skokie | IL | Electrical Equipment, Appliance & Component Manufacturing335312 | — | ◇ UNVERIFIED |
| ACAmerican/jebco CORP | Franklin Park | IL | Fabricated Metal Product Manufacturing332722 | — | ◇ UNVERIFIED |
| ALAmerican Litho INC | Carol Stream | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| ALAmerican Litho INC | Schaumburg | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| ALAmerican Lock CO | Crete | IL | Fabricated Metal Product Manufacturing332510 | — | ◇ UNVERIFIED |
| ALAmerican Louver CO | Skokie | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| AMAmerican Midwest Chrome Plating & Polishing | Chicago | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| APAmerican Precision Castings INC | Chicago | IL | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| ARAmerican Rack CO | Chicago | IL | Fabricated Metal Product Manufacturing332999 | — | ◇ UNVERIFIED |
| ASAmerican Stair CORP | Romeoville | IL | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| ASAmerican Stone Mix, INC. - Franklin Park | Franklin Park | IL | Petroleum and Coal Products Manufacturing324122 | — | ◇ UNVERIFIED |
| ASAmerican Sugar Refining INC | Chicago | IL | Food Manufacturing311999 | — | ◇ UNVERIFIED |
| ASAmerican Supply INC | Morris | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| ATAmerican Thiessen LLC | Chicago | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
 American Wilbert Vault CORP | Chicago | IL | Nonmetallic Mineral Product Manufacturing327331 | — | ◇ UNVERIFIED |
| AIAmerichem INC | Elgin | IL | Chemical Manufacturing325991 | — | ◇ UNVERIFIED |
| ACAmericoats Coatings International INC | Franklin Park | IL | Chemical Manufacturing325998 | — | ◇ UNVERIFIED |
| AIAmericoats-coatings International INC | Franklin Park | IL | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| ACAmerock CORP | Rockford | IL | Fabricated Metal Product Manufacturing332510 | — | ◇ UNVERIFIED |
| AMAmes Metal Products CO | Chicago | IL | Primary Metal Manufacturing331491 | — | ◇ UNVERIFIED |
| ATAmes True Temper | Clay City | IL | Wood Product Manufacturing321113 | — | ◇ UNVERIFIED |
| ADAmilan Distributors INC | Bensenville | IL | Fabricated Metal Product Manufacturing332812 | — | ◇ UNVERIFIED |
| ACAmish Crafters INC | Paris | IL | Machinery Manufacturing333515 | — | ◇ UNVERIFIED |
| ABAmmeraal Beltech INC | Skokie | IL | Apparel Manufacturing315990 | — | ◇ UNVERIFIED |
| AMAmpco Metal INC. | Arlington Heights | IL | Primary Metal Manufacturing331525 | — | ◇ UNVERIFIED |
| ASAmrize South Central INC. | Cave in Rock | IL | Machinery Manufacturing333131 | — | ◇ UNVERIFIED |
| ALAmsive, LLC | Bolingbrook | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| ACAnchor Coupling CO | Dixon | IL | Fabricated Metal Product Manufacturing332912 | — | ◇ UNVERIFIED |
| AAnderson | Chicago | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
| AAndersonbrecon | Rockford | IL | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| AFAnderson Fittings | Oak Forest | IL | Fabricated Metal Product Manufacturing332919 | — | ◇ UNVERIFIED |
| AHAnderson Heat Treating INC | Rockford | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| ACAndrew CORP | Joliet | IL | Computer and Electronic Product Manufacturing334220 | — | ◇ UNVERIFIED |
| ALAndrew LLC | Orland Park | IL | Computer and Electronic Product Manufacturing334210 | — | ◇ UNVERIFIED |
| AIAnets INC | Northbrook | IL | Machinery Manufacturing333294 | — | ◇ UNVERIFIED |
| AIAnpec Ind | Pecatonica | IL | Fabricated Metal Product Manufacturing332710 | 20-99 | ◇ UNVERIFIED |
| APAntioch Packing House | Antioch | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| APApache Products CO | Belvidere | IL | Plastics and Rubber Products Manufacturing326140 | — | ◇ UNVERIFIED |
| ADApco Deburring & Polishing INC | Chicago | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| ACApcon CORP | Fairmount | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| APApollo Plastics | Chicago | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| AAAppetizers and INC | Chicago | IL | Food Manufacturing311412 | — | ◇ UNVERIFIED |
| ARAppliance Recylcers INC | Granite City | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| AAApplied Acoustics Intl | Chicago Heights | IL | Transportation Equipment Manufacturing336390 | — | ◇ UNVERIFIED |
| ACApplied Composites | Saint Charles | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| ASApv Service Center | Schaumburg | IL | Machinery Manufacturing333241 | — | ◇ UNVERIFIED |
| AIAquion INC | Roselle | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| AWAquion Water Treatment Products LLC Awtp Holding LLC | Elk Grove Village | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| AGArcar Graphics LLC | West Chicago | IL | Chemical Manufacturing325910 | — | ◇ UNVERIFIED |
| AHArcelormittal Hennepin LLC | Hennepin | IL | Primary Metal Manufacturing331111 | — | ◇ UNVERIFIED |
