| CUChep USA | Aurora | IL | Wood Product Manufacturing321920 | — | ◇ UNVERIFIED |
| CBChester Bross Construction CO | Kinderhook | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CBChester Bross Construction CO | Loraine | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CFChester Foundry | Chester | IL | Primary Metal Manufacturing331420 | — | ◇ UNVERIFIED |
| CEChevron Environmental Management CO | Medinah | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CAChicago Allis Mfg CORP | Chicago | IL | Plastics and Rubber Products Manufacturing326299 | — | ◇ UNVERIFIED |
| CAChicago Aluminum Castings CO INC | Chicago | IL | Primary Metal Manufacturing331524 | — | ◇ UNVERIFIED |
| CBChicago Baking CO | Chicago | IL | Food Manufacturing311812 | — | ◇ UNVERIFIED |
| CBChicago Block CO INC | Forest View | IL | Computer and Electronic Product Manufacturing334512 | — | ◇ UNVERIFIED |
| CBChicago Board of Education | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CCChicago, City of | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CDChicago Decal CO | Burr Ridge | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| CDChicago Dowel CO INC | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CFChicago Faucet CO | Des Plaines | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| CFChicago Finished Metals INC | Bridgeview | IL | Nonmetallic Mineral Product Manufacturing327993 | — | ◇ UNVERIFIED |
| CGChicago Gaming Cabinets | Chicago | IL | Furniture and Related Product Manufacturing337110 | — | ◇ UNVERIFIED |
| CHChicago Heights Processing | Chicago Heights | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CHChicago Heights Railcar INC | Chicago Heights | IL | Transportation Equipment Manufacturing336510 | — | ◇ UNVERIFIED |
| CWChicagoland Warehouse and Transportation, INC. | Bridgeview | IL | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
| CWChicagoland Wholesale Mulch | Crest Hill | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CMChicago Metallic Corp-interfinish Plant | Bridgeview | IL | Chemical Manufacturing325611 | — | ◇ UNVERIFIED |
| CPChicago Plating INC | Chicago | IL | Fabricated Metal Product Manufacturing332313 | — | ◇ UNVERIFIED |
| CPChicago Press CORP | Chicago | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| CSChicago Specialties, LLC | Chicago | IL | Chemical Manufacturing325100 | — | ◇ UNVERIFIED |
| CSChicago Steel Rule Die & Fabricators CO | Chicago | IL | Fabricated Metal Product Manufacturing332812 | — | ◇ UNVERIFIED |
| CSChicago Sterilization Services | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CTChicago Title Land Trust | Chicago | IL | Fabricated Metal Product Manufacturing332439 | — | ◇ UNVERIFIED |
| CTChicago Title Land Trust CO | Bloomington | IL | Electrical Equipment, Appliance & Component Manufacturing335311 | — | ◇ UNVERIFIED |
| CTChicago Tribune Company | Schaumburg | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| CMChilo Manufacturing & Plating Company | Chicago | IL | Chemical Manufacturing325998 | — | ◇ UNVERIFIED |
| CPChris Plating | Northbrook | IL | Primary Metal Manufacturing331221 | — | ◇ UNVERIFIED |
| CBChrist Bros Products LLC | Collinsville | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CBChrist Bros Products LLC | Dupo | IL | Petroleum and Coal Products Manufacturing324121 | — | ◇ UNVERIFIED |
| CEChristofano Equipment INC | Harwood Heights | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CLChroma Liquid Color CORP | Chicago Heights | IL | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| CIChrometec Industries LLC | Lombard | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| CPChromold Plating INC | Mchenry | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| CVCiba Vision CORP | Des Plaines | IL | Miscellaneous Manufacturing339115 | — | ◇ UNVERIFIED |
| CPCima Plastics CORP | West Chicago | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| CRCimco Recycling | Marion | IL | Primary Metal Manufacturing331492 | — | ◇ UNVERIFIED |
| CRCimco Recycling Ottawa INC | Ottawa | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CRCimco Resources | Rock Falls | IL | Fabricated Metal Product Manufacturing332510 | — | ◇ UNVERIFIED |
| CKCircle K 6758 | Oak Park | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| CMCircle Metal Specialties INC | Alsip | IL | Fabricated Metal Product Manufacturing332116 | — | ◇ UNVERIFIED |
| CSCircle Smelting CORP | Beckemeyer | IL | Primary Metal Manufacturing331000 | — | ◇ UNVERIFIED |
| CECircuit Etching Technics INC | Elk Grove Village | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| CWCircuit World INC | Itasca | IL | Computer and Electronic Product Manufacturing334412 | — | ◇ UNVERIFIED |
| CTCirqon Technologies CORP | Gurnee | IL | Computer and Electronic Product Manufacturing334419 | — | ◇ UNVERIFIED |
| CDCitation Dycast | Lake Zurich | IL | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
| CTCi Telecom | Rantoul | IL | Computer and Electronic Product Manufacturing334210 | — | ◇ UNVERIFIED |
