| CCaraustar | Ontario | CA | Paper Manufacturing322130 | — | ◇ UNVERIFIED |
| CICargill INC | Ontario | CA | Food Manufacturing311225 | — | ◇ UNVERIFIED |
| CCCarny Chem CORP | Ontario | CA | Miscellaneous Manufacturing339113 | — | ◇ UNVERIFIED |
| CCCarrington College Ontario | Ontario | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| CICastle Industries INC. of Ca. | Ontario | CA | Fabricated Metal Product Manufacturing332322 | — | ◇ UNVERIFIED |
| CHCatalyst Hydraulic Machining | Ontario | CA | Computer and Electronic Product Manufacturing334511 | — | ◇ UNVERIFIED |
| CDC & D Plastics | Ontario | CA | Miscellaneous Manufacturing339113 | — | ◇ UNVERIFIED |
| CZC&d Zodiac Inc./zodiac Aerospace | Ontario | CA | Computer and Electronic Product Manufacturing334511 | — | ◇ UNVERIFIED |
 Certified Aviation Services LLC | Ontario | CA | Transportation Equipment Manufacturing336413 | — | ◇ UNVERIFIED |
| CPChander Prakash Mittal and Rekha Chander Mittal, Trustees of The Mittal Family T | Ontario | CA | Transportation Equipment Manufacturing336390 | — | ◇ UNVERIFIED |
| CBCherry Blossom, J Diaz & E Diaz, INC | Ontario | CA | Furniture and Related Product Manufacturing337122 | — | ◇ UNVERIFIED |
| CLChristian Life LLC | Ontario | CA | Machinery Manufacturing333511 | — | ◇ UNVERIFIED |
| CICinco Iron Works INC | Ontario | CA | Fabricated Metal Product Manufacturing332312 | — | ◇ UNVERIFIED |
| CSCitistaff Solutions, INC. | Ontario | CA | Furniture and Related Product Manufacturing337127 | — | ◇ UNVERIFIED |
| COCity of Ontario | Ontario | CA | Primary Metal Manufacturing331210 | — | ◇ UNVERIFIED |
| COCity of Ontario Fire Department | Ontario | CA | Nonmetallic Mineral Product Manufacturing327999 | — | ◇ UNVERIFIED |
| CPCNC Powder Coating | Ontario | CA | Fabricated Metal Product Manufacturing332811 | — | ◇ UNVERIFIED |
| CBColeman Brothers Distillation LLC | Ontario | OR | Food Manufacturing311942 | — | ◇ UNVERIFIED |
| CCompu-metal,inc | Ontario | CA | Machinery Manufacturing333415 | — | ◇ UNVERIFIED |
| CWCountry Wide Pallets | Ontario | CA | Wood Product Manufacturing321920 | — | ◇ UNVERIFIED |
| CACoveris America | Ontario | CA | Paper Manufacturing322220 | — | ◇ UNVERIFIED |
| CPCrown Paper Converting | Ontario | CA | Paper Manufacturing322299 | — | ◇ UNVERIFIED |
| CICrst INC | Ontario | CA | Transportation Equipment Manufacturing336212 | — | ◇ UNVERIFIED |
| CFCta Fixtures INC | Ontario | CA | Furniture and Related Product Manufacturing337110 | — | ◇ UNVERIFIED |
| CECupertino Electric INC | Ontario | CA | Chemical Manufacturing325411 | — | ◇ UNVERIFIED |
| DPDan Parish LTD | Ontario | CA | Furniture and Related Product Manufacturing337215 | — | ◇ UNVERIFIED |
| DKDavid Kennedy | Ontario | CA | Machinery Manufacturing333924 | — | ◇ UNVERIFIED |
| DIDba International Machinery CO | Ontario | CA | Machinery Manufacturing333518 | — | ◇ UNVERIFIED |
| DEDee Engineering | Ontario | CA | Transportation Equipment Manufacturing336390 | — | ◇ UNVERIFIED |
| DFDefoe Furniture 4 Kids INC | Ontario | CA | Furniture and Related Product Manufacturing337122 | — | ◇ UNVERIFIED |
| DDDemert & Dougherty INC | Ontario | CA | Chemical Manufacturing325620 | — | ◇ UNVERIFIED |
| DMDFX Manufactory | Ontario | CA | Chemical Manufacturing325411 | — | ◇ UNVERIFIED |
| DWD&g Warren Corporation Dba Warren Graphics | Ontario | CA | Printing and Related Support Activities323113 | — | ◇ UNVERIFIED |
| DPDinamic Pallets | Ontario | CA | Wood Product Manufacturing321920 | — | ◇ UNVERIFIED |
| DWDiversey / Waxie | Ontario | CA | Chemical Manufacturing325612 | — | ◇ UNVERIFIED |
| DJDoing Jin America INC | Ontario | CA | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
| DHDouglas-kent Holdings, LLC | Ontario | CA | Primary Metal Manufacturing331221 | — | ◇ UNVERIFIED |
 Dunn-edwards Corporation | Ontario | CA | Chemical Manufacturing325510 | — | ◇ UNVERIFIED |
| DDDurable Dies Inc. | Ontario | CA | Chemical Manufacturing325130 | — | ◇ UNVERIFIED |
| DDurimex,inc. | Ontario | CA | Transportation Equipment Manufacturing336320 | — | ◇ UNVERIFIED |
| DADym Apartments LLC | Ontario | CA | Transportation Equipment Manufacturing336350 | — | ◇ UNVERIFIED |
| DSDynamic Supply INC | Ontario | CA | Chemical Manufacturing325910 | — | ◇ UNVERIFIED |
| DTDynamic Towing | Ontario | CA | Transportation Equipment Manufacturing336214 | — | ◇ UNVERIFIED |
| EPEaa Pacific INC | Ontario | CA | Fabricated Metal Product Manufacturing332710 | — | ◇ UNVERIFIED |
| ELE & L Quality Machining | Ontario | CA | Fabricated Metal Product Manufacturing332710 | — | ◇ UNVERIFIED |
| EPEclipse Painting Dba James Litho | Ontario | CA | Printing and Related Support Activities323117 | — | ◇ UNVERIFIED |
| EAEco Absorbent Technologies, INC | Ontario | CA | Chemical Manufacturing325612 | — | ◇ UNVERIFIED |
| EOElements of Style | Ontario | CA | Furniture and Related Product Manufacturing337110 | — | ◇ UNVERIFIED |
| EPElmore Products | Ontario | CA | Transportation Equipment Manufacturing336390 | — | ◇ UNVERIFIED |
| ECEnviro Compliance Solutions | Ontario | CA | Machinery Manufacturing333923 | — | ◇ UNVERIFIED |
