| SBSchultz Barrel & Drum | Chicago | IL | Plastics and Rubber Products Manufacturing326199 | — | ◇ UNVERIFIED |
| SBSchulze & Burch Biscuit CO | Chicago | IL | Food Manufacturing311821 | — | ◇ UNVERIFIED |
| SPScientific Plating CO. INC | Chicago | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| SJScully Jones CORP | Chicago | IL | Machinery Manufacturing333515 | — | ◇ UNVERIFIED |
| SPService Products INC | Chicago | IL | Wood Product Manufacturing321219 | — | ◇ UNVERIFIED |
| SWService Web Offset CORP | Chicago | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| SGSethness Greenleaf INC | Chicago | IL | Food Manufacturing311930 | — | ◇ UNVERIFIED |
| SWSeven Worldwide INC | Chicago | IL | Printing and Related Support Activities323120 | — | ◇ UNVERIFIED |
| SCSf Ch1, LLC | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| SBSh Bell CO | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| SSSheridan Sand & Gravel | Chicago | IL | Nonmetallic Mineral Product Manufacturing327320 | — | ◇ UNVERIFIED |
| SWSherwin Williams CO | Chicago | IL | Chemical Manufacturing325130 | — | ◇ UNVERIFIED |
| SCSilgan Closures LLC #35 | Chicago | IL | Fabricated Metal Product Manufacturing332115 | — | ◇ UNVERIFIED |
| SHSk Hand Tool CORP | Chicago | IL | Fabricated Metal Product Manufacturing332212 | — | ◇ UNVERIFIED |
| SASmall Assemblies INC | Chicago | IL | Primary Metal Manufacturing331523 | — | ◇ UNVERIFIED |
| SASmall Assemblies INC | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| SSSmg/ Scott Petersen | Chicago | IL | Food Manufacturing311612 | — | ◇ UNVERIFIED |
| SBSmith Brothers CO | Chicago | IL | Food Manufacturing311352 | — | ◇ UNVERIFIED |
| SCSolo Cup CO | Chicago | IL | Paper Manufacturing322215 | — | ◇ UNVERIFIED |
| SPSoodik Printing CO | Chicago | IL | Textile Mills313310 | — | ◇ UNVERIFIED |
| SCSouth Chicago Property Development | Chicago | IL | Nonmetallic Mineral Product Manufacturing327410 | — | ◇ UNVERIFIED |
| SISpecialloy INC | Chicago | IL | Primary Metal Manufacturing331420 | — | ◇ UNVERIFIED |
| SPSpecified Plating CO | Chicago | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| SCSpraylat CORP Il | Chicago | IL | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| STStar Thermoplastic | Chicago | IL | Chemical Manufacturing325991 | — | ◇ UNVERIFIED |
| SDSterling Disposable Products | Chicago | IL | Furniture and Related Product Manufacturing337910 | — | ◇ UNVERIFIED |
| SPStewarts Private Blend Foods INC | Chicago | IL | Food Manufacturing311920 | — | ◇ UNVERIFIED |
| SMStrategic Materials INC | Chicago | IL | Nonmetallic Mineral Product Manufacturing327212 | — | ◇ UNVERIFIED |
| SMStrategic Materials INC | Chicago | IL | Nonmetallic Mineral Product Manufacturing327215 | — | ◇ UNVERIFIED |
| SCStrombecker CORP | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| SAStromberg Allen & CO | Chicago | IL | Printing and Related Support Activities323110 | — | ◇ UNVERIFIED |
 Sun Chemical | Chicago | IL | Chemical Manufacturing325910 | — | ◇ UNVERIFIED |
| SGSuperior Graphite CO | Chicago | IL | Petroleum and Coal Products Manufacturing324199 | — | ◇ UNVERIFIED |
| SMSuperior Manufacturing Group INC | Chicago | IL | Chemical Manufacturing325612 | — | ◇ UNVERIFIED |
| TFTag Furnishings Group | Chicago | IL | Furniture and Related Product Manufacturing337122 | — | ◇ UNVERIFIED |
| TSTempel Steel Company LLC | Chicago | IL | Fabricated Metal Product Manufacturing332116 | — | ◇ UNVERIFIED |
| TCTennant Coatings INC | Chicago | IL | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| TMTerrell Materials CORP | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| TMTerrell Materials CORP | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| TOThe Original Instant Printing | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| TITin INC D/b/a Temple - Inland | Chicago | IL | Paper Manufacturing322213 | — | ◇ UNVERIFIED |
| TLTrans Load | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| TPTribune Properties INC | Chicago | IL | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| TVTrue Value Manufacturing CO | Chicago | IL | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| UIUgn INC | Chicago | IL | Transportation Equipment Manufacturing336390 | — | ◇ UNVERIFIED |
| UPUnion Pacific Railroad | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| UPUnion Partners Upx CORP Dba Lamination Specialities CORP LLC | Chicago | IL | Miscellaneous Manufacturing339999 | — | ◇ UNVERIFIED |
| UAUnited American Metal | Chicago | IL | Primary Metal Manufacturing331420 | — | ◇ UNVERIFIED |
| UMUnited Metal Finishers | Chicago | IL | Fabricated Metal Product Manufacturing332813 | — | ◇ UNVERIFIED |
| UDUS Diecasting INC | Chicago | IL | Primary Metal Manufacturing331521 | — | ◇ UNVERIFIED |
